ASoC: msm: Fix for setting the Sample Rate for BT

Add the mixer controls in kcontrols for setting
BT sample rate.

The actual sample rate is passed in the mixer
control instead of passing an enum value in the
mixer control.

Change-Id: I4029eedbedac2c4eece036b63cec895c69952140
Signed-off-by: Vicky Sehrawat <vickys@codeaurora.org>