vidc: vdec: Pass alignment flag to mapping api's.

Mapping api by default assumes 4K alignment.
Video core requires output buffer to be aligned
to 8K.This change will pass aligment information to
the mapper API.

Change-Id: Iea630649476946614dfdbdf5150d97cf46a0ba42
Signed-off-by: Mohan Kumar Gubbihalli Lachma Naik <mgubbi@codeaurora.org>