[SOC_RESET_ME] Add PeerSoCId mapping

SOC_RESET_ME handler will based on pldmd daemon instance id
(daemon input parameter --instance) to know which SoC to reset
Add a PeerSoCId wrapping class to mapping input instance to
the SoCId and expose this as immutable global information to
the SoCResetMe handler.

Tested:
[==========] Running 3 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 3 tests from PeerSoCIdTest
[ RUN      ] PeerSoCIdTest.SetWithPldmdInstanceParam
[       OK ] PeerSoCIdTest.SetWithPldmdInstanceParam (0 ms)
[ RUN      ] PeerSoCIdTest.SetWithPldmdInstanceParamCN_1
[       OK ] PeerSoCIdTest.SetWithPldmdInstanceParamCN_1 (0 ms)
[ RUN      ] PeerSoCIdTest.SetWithPldmdInstanceParamCN_2
[       OK ] PeerSoCIdTest.SetWithPldmdInstanceParamCN_2 (0 ms)
[----------] 3 tests from PeerSoCIdTest (0 ms total)

[----------] Global test environment tear-down
[==========] 3 tests from 1 test suite ran. (0 ms total)
[  PASSED  ] 3 tests.

Change-Id: I3d432f5dfcfa6a8751d1779bf7dac719e8532dc3
Signed-off-by: Dan Zhang <zhdaniel@google.com>