msm: msm_fb: remove mmio access through mmap

Disable access to mm io and add
appropriate range checks to ensure valid accesses
through framebuffer mmap. This prevents illegal
access into memory.

CRs-Fixed: 474706
Change-Id: If25166f2732433ef967e99c716440030b567aae9
Signed-off-by: Manoj Rao <manojraj@codeaurora.org>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>

Conflicts:

	drivers/video/msm/msm_fb.c