ASoC: msm: q6: set volume on all channels agnostic to num channel

We were seeing an issue of surround channels not getting affected
with volume change, because we were receiving wrong no of channels
from metadata and decoded bitstream is not available at this point
so calling set volume with equal gain on all the channels and call
stereo specific only when we require different volumes on both
channels

CRs-Fixed: 502349
Change-Id: I150dd44380a0e1e18f3521bf7e1876d6c633bbb2
Signed-off-by: Jitendra Singh Naruka <jnaruk@codeaurora.org>