msm: media: Allocate extra memory after alignment

Existing memory allocation considers alignment after
adding the extra lines needed by hardware. This does
not increase the buffer size by the required size
increment. Add the increment after aligning the
scanlines to prevent out-of-bounds access.

Change-Id: I5f6ff7cec99e4cb5f94edda506bd1740b9b38242
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>