Allow a device to define the max number of service groups in init.h

Certain proprieatary binaries (such as tcmd for instance) require
more than 12 supplementary service groups.  By definiing:
TARGET_NR_SVC_SUPP_GIDS := in BoardConfig this can now be changed
per device.

Change-Id: Iab853836a028147c051be21e39575635cb463dd1
Signed-off-by: dhacker29 <davidhackerdvm@gmail.com>