ASoC: msm: qdsp6v2: Fix for Rx device mute in voice call

Since Rx device mute command ramp duration is not initialized,
it takes random value which results Rx device mute does not
work. Initialize ramp duration to default value.

Change-Id: I913f2b1958d896ddda7239b4b0ce331495084145
Signed-off-by: Vidyakumar Athota <vathota@codeaurora.org>