mctp-controller-init-v2: Add SKIP_BUS to specify the bus to skip

Tested:
Set SKIP_BUS = "mctpi3c6 mctpi3c10"
root@bmc:~# journalctl -u mctp-controller-init.service
Apr 27 23:35:22 bmc systemd[1]: Starting Initialize mctp controller for all MCTP interfaces...
Apr 27 23:35:23 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c1 up network 1
Apr 27 23:35:23 bmc mctp-controller-init.sh[588]: mctp addr add 254 dev mctpi2c1
Apr 27 23:35:23 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c2 up network 1
Apr 27 23:35:23 bmc mctp-controller-init.sh[588]: mctp addr add 253 dev mctpi2c2
Apr 27 23:35:23 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c4 up network 1
Apr 27 23:35:23 bmc mctp-controller-init.sh[588]: mctp addr add 252 dev mctpi2c4
Apr 27 23:35:23 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c5 up network 1
Apr 27 23:35:24 bmc mctp-controller-init.sh[588]: mctp addr add 251 dev mctpi2c5
Apr 27 23:35:24 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c9 up network 1
Apr 27 23:35:24 bmc mctp-controller-init.sh[588]: mctp addr add 250 dev mctpi2c9
Apr 27 23:35:24 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c10 up network 1
Apr 27 23:35:24 bmc mctp-controller-init.sh[588]: mctp addr add 249 dev mctpi2c10
Apr 27 23:35:24 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c16 up network 1
Apr 27 23:35:24 bmc mctp-controller-init.sh[588]: mctp addr add 248 dev mctpi2c16
Apr 27 23:35:24 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c17 up network 1
Apr 27 23:35:25 bmc mctp-controller-init.sh[588]: mctp addr add 247 dev mctpi2c17
Apr 27 23:35:25 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c18 up network 1
Apr 27 23:35:25 bmc mctp-controller-init.sh[588]: mctp addr add 246 dev mctpi2c18
Apr 27 23:35:25 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c19 up network 1
Apr 27 23:35:25 bmc mctp-controller-init.sh[588]: mctp addr add 245 dev mctpi2c19
Apr 27 23:35:25 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c20 up network 1
Apr 27 23:35:26 bmc mctp-controller-init.sh[588]: mctp addr add 244 dev mctpi2c20
Apr 27 23:35:26 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c21 up network 1
Apr 27 23:35:26 bmc mctp-controller-init.sh[588]: mctp addr add 243 dev mctpi2c21
Apr 27 23:35:26 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c24 up network 1
Apr 27 23:35:27 bmc mctp-controller-init.sh[588]: mctp addr add 242 dev mctpi2c24
Apr 27 23:35:27 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c25 up network 1
Apr 27 23:35:27 bmc mctp-controller-init.sh[588]: mctp addr add 241 dev mctpi2c25
Apr 27 23:35:27 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c26 up network 1
Apr 27 23:35:28 bmc mctp-controller-init.sh[588]: mctp addr add 240 dev mctpi2c26
Apr 27 23:35:28 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c27 up network 1
Apr 27 23:35:28 bmc mctp-controller-init.sh[588]: mctp addr add 239 dev mctpi2c27
Apr 27 23:35:28 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c28 up network 1
Apr 27 23:35:29 bmc mctp-controller-init.sh[588]: mctp addr add 238 dev mctpi2c28
Apr 27 23:35:29 bmc mctp-controller-init.sh[588]: mctp link set mctpi2c29 up network 1
Apr 27 23:35:29 bmc mctp-controller-init.sh[588]: mctp addr add 237 dev mctpi2c29
Apr 27 23:35:29 bmc mctp-controller-init.sh[588]: mctp link set mctpi3c4 up network 1
Apr 27 23:35:30 bmc mctp-controller-init.sh[588]: mctp addr add 236 dev mctpi3c4
Apr 27 23:35:30 bmc mctp-controller-init.sh[588]: mctp link set mctpi3c5 up network 1
Apr 27 23:35:30 bmc mctp-controller-init.sh[588]: mctp addr add 235 dev mctpi3c5
Apr 27 23:35:30 bmc mctp-controller-init.sh[588]: Skip bringing up MCTP bus mctpi3c6 as it is in SKIP_BUS list
Apr 27 23:35:30 bmc mctp-controller-init.sh[588]: mctp link set mctpi3c8 up network 1
Apr 27 23:35:30 bmc mctp-controller-init.sh[588]: mctp addr add 234 dev mctpi3c8
Apr 27 23:35:30 bmc mctp-controller-init.sh[588]: mctp link set mctpi3c9 up network 1
Apr 27 23:35:31 bmc mctp-controller-init.sh[588]: mctp addr add 233 dev mctpi3c9
Apr 27 23:35:31 bmc mctp-controller-init.sh[588]: Skip bringing up MCTP bus mctpi3c10 as it is in SKIP_BUS list
Apr 27 23:35:31 bmc systemd[1]: mctp-controller-init.service: Deactivated successfully.
Apr 27 23:35:31 bmc systemd[1]: Finished Initialize mctp controller for all MCTP interfaces.
Apr 27 23:35:31 bmc systemd[1]: mctp-controller-init.service: Consumed 3.774s CPU time, 2.6M memory peak.

Google-Bug-Id: 500205657
Change-Id: I8fb272722a7702b02f4ebf4695cb2533d379bc97
Signed-off-by: Harvey Wu <harvey.wu@quanta.corp-partner.google.com>