fbdev: msm: Fix iova alignment for smmu mappings

Smmu driver expects all iova addresses to be
1Mb aligned. Additionally, 32 bit mode requires
128Mb alignment.

Change-Id: I001642d8e6943f0595377b6b12d198e3e62899f2
Signed-off-by: Animesh Kishore <animeshk@codeaurora.org>