MAC address comparison

Fixes:
    - Move common keywords from test suites to
      lib/bmc_network_utils.robot
    - Add new python function to compare the MAC address.

Resolves  openbmc/openbmc-test-automation#1261

Change-Id: Ie3447d6a82679152ccd0b571ade63a1f1b71fd05
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
4 files changed