ASoC: wcd9320: Fix for audio recording

If multiple mixer widgtes share the same kcontrol,ASoC framework
will create common controls. For audio capture usecase we need
each AIF cap mixer widget to have its own control.
Change creates control for each of the AIF capture mixer widgets.

Change-Id: Id178c7154cd50c21fa8b6715c16e6db950ba1d4c
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>