msm: vidc: add check to ensure buffer size is 4K aligned

Input and output buffer size must be 4K aligned for both
encoder and decoder session. So reject the session during
msm_vidc_qbuf, if alloc_len is not 4K aligned.

Change-Id: If555f26f1658ce50e12a8533cb9d59134da0aa81
Signed-off-by: Govindaraj Rajagopal <grajagop@codeaurora.org>