ASoC: msm: qdsp6v2: updating downmix/pan_scale control type to bytes

Change the downmix/pan_scale control data type from integer to bytes
to make it compatible across different archs.

Change-Id: I9282673dc1e124185d7c545206bba31966b803dc
Signed-off-by: Varun Balaraj <varunb@codeaurora.org>