init: Add vendor-specific initialization hooks.

Allow optional vendor-specific initializations
within init.  This can be used for runtime
initialization setup that init rc scripts do
not support.

Issue: FP2P-327
Change-Id: I7623a0d59b18f9ec8e3623958e2f7ccd72b877bf
(cherry picked from commit 1821d21883eeac2d77c1ae6b915ce0ca0de557c3)
6 files changed