ASoC: msm: Add DSP support for SRS on A2DP

- Enabling or disabling SRS effects on music playback on
  A2DP doesn't have any effect.
- Cause for this is, parameters for SRS effects were not send
  if the device is A2DP.
- Fix is to add a new kcontrol for A2DP and use the new kcontrol
  to send SRS parameters for A2DP case.

Signed-off-by: Sharad Sangle <assangle@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>