hwc : Compilation issue fix.

    Added unsed-paramter to C_FLAGS
    Removed page.h
    Included sync.h

Change-Id: I86db10f108132a7ebc7d4d56be4c18a6ad5017f7

Conflicts:
	common.mk
	libgenlock/Android.mk
	libhwcomposer/hwc_copybit.cpp