ASoC: Intel: Fix stream volume set no effect issue on Broadwell

The volume setting control for capture stream doesn't take effect on intel
Broadwell platform. Root cause it at 2 points:
1. set stream volume with channel=2 is wrongly bapassed;
2. the saved stream volume should be restored after stream is commit.

Here correct these 2 items to fix the stream volume set issue.

Signed-off-by: Jie Yang <yang.jie@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>