Make Graphite Optimizations a config option to easily enable/disable it

Signed-off-by: Dan Trifan <jimsth@gmail.com>

Conflicts:
	Makefile
	arch/arm/configs/hammerhead_defconfig

Signed-off-by: DHOMD <DHO@dho.im>
 defconfig: enable graphite optimizations

 * They seem to work without issue, while giving a performance boost (On HH, trying on 700)
 * Credits @metalspring