msm: vidc: Adjust GOP size when layers are enabled

When layers are enabled GOP size should always be multiple
of 2 ^ num_enhancement_layers. Based on this adjust GOP
size during start streaming and also when dynamic GOP size
is set.

CRs-Fixed: 2368458
Change-Id: I31dcf6217e4bb66e4a0c9621f30767e34a9cde5b
Signed-off-by: Vaibhav Deshu Venkatesh <vdeshuve@codeaurora.org>