Add CXL detection to BMC's pcie.cfg

Set CXL bit in pcie bifurcation data for CXL devices

Tested:
Without CXL Fru:

Before=>
00000000  05 01 10 01 10 01 10 01  04 01 04                 |...........|
0000000b
00000000  05 01 10 01 10 01 10 01  04 01 04                 |...........|
0000000b

After=>
00000000  05 01 10 01 10 01 10 01  04 01 04                 |...........|
0000000b
00000000  05 01 10 01 10 01 10 01  04 01 04                 |...........|
0000000b

With CXL Fru: (BBUS164=2620:15c:2c3:a805:22f0:94ff:fe53:68b8)

Before=>
00000000  04 02 08 08 02 08 08 01  10 01 01                 |...........|
0000000b
00000000  04 02 08 08 02 08 08 01  10 01 01                 |...........|
0000000b

After=>
00000000  04 02 88 08 02 88 08 01  10 01 01                 |...........|
0000000b
00000000  04 02 88 08 02 88 08 01  10 01 01                 |...........|
0000000b

Google-Bug-Id: 427566786
Change-Id: I90a7ce705e532023f769f4c9f2231b3805c9a75b
Signed-off-by: Konda Reddy Kachana <kkachana@google.com>