zram & zsmalloc: update to msm-3.7 version

* Remove old zram version in drivers/zram
* Update zram & zsmalloc to latest unchanged msm-3.7 (will
  add compatibility in separate change).

Change-Id: I05bed573cc37a5b04ff0d1ac67fbd60632b52c05

Conflicts:
	drivers/Kconfig
	drivers/Makefile
	drivers/staging/Kconfig
	drivers/staging/Makefile
	drivers/staging/zram/Kconfig
	drivers/staging/zram/Makefile
	drivers/staging/zram/xvmalloc.c
	drivers/staging/zram/xvmalloc.h
	drivers/staging/zram/xvmalloc_int.h
	drivers/staging/zram/zram_drv.c
	drivers/staging/zram/zram_drv.h
	drivers/staging/zram/zram_sysfs.c