Test rear identify system LEDs of Witherspoon system.

This change includes:
   - Added test cases to turn on/off rear identify LED.
   - Skipped rear identify LED in NA systems.

Resolves openbmc/openbmc-test-automation#755

Change-Id: I1a7376d7815fa0a9ef38e42ec32098a588ecd28f
Signed-off-by: Rahul Maheshwari <rahulmaheshwari@in.ibm.com>
3 files changed