meta-google: gbmc-ncsi-config: Fix ND answering without bridge

We want to answer all of the possible BMC addresses for neighbor
discovery in cases where the bridge is not present on the BMC image.

Change-Id: Id8f0f929bbac2c8526a5ab87b410124357e4bd3d
Signed-off-by: William A. Kennington III <wak@google.com>