init: Check for symlinks with lstat() not open()

Using open() with an O_NOFOLLOW flag will result in a file falsely
being determined to be a symlink if the open fails for another
reason.

For example, a character device that isn't ready due to the
underlying hardware not being initialized yet will fail to open()

An example of this are any CG2900 device files prior to
execution of ste-cg29xx_ctrl

This uses lstat() instead of open() with O_NOFOLLOW to check
whether a file is a symlink or not.

Change-Id: Ie0d8d94b426c84c29b1b04d41a4cc15536cb307c
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>