qdutils: Default to GPU composition

If composition type is not set, default to GPU composition.
This is because CPU composition is not supported from MR1 onwards

Change-Id: I951dcb5586a8dbcfbe73cd7292d0f1690d6528ba

Conflicts:
	libqdutils/comptype.h
gralloc: Remove update rect

SurfaceFlinger does not use this feature any more.
Removing this to avoid usage of reserved flags.
If this is needed again, it can be added with metadata
in the display commit ioctl

Change-Id: Iaf3f14a910ad64c83abb0910fad4a999b663c545