msm: mdss: use framebuffer line length as base layer stride

Adreno graphics core expects framebuffer to be aligned to 32 bytes, this
alignment is observed in framebuffer and needs to be used for base
layer. If not followed stride corruption can be seen for frames rendered
by Adreno GPU.

Change-Id: Iea5e729dc4e4613bd7270d7bcf616cff6377109a
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>