msm: kgsl: Add arch_mmap_check() stub definition

Add a stub definition for arch_mmap_check() in kgsl.c for
situations where the function is not defined, similar to the
stub definition in mm/mmap.c

Change-Id: I2d0f7f8c76f35cbec1554893433199e256f76df4
Signed-off-by: Shrenuj Bansal <shrenujb@codeaurora.org>