Add zram for android optimization

Conflicts:

	drivers/staging/zram/Kconfig
	drivers/staging/zram/zram_drv.c
	drivers/staging/zram/zram_drv.h
	drivers/staging/zram/zram_sysfs.c (reverse-merged from commit 44c3a3bc08ec3d6d4edf5d1130d9f9675c742d1e)