ASoC: msm8x16-wcd: fix widget definition for RDAC2 MUX

RDAC2 MUX define requires to be normal SOC_DAPM_ENUM
widget but it is using MSM8X16_WCD_DEC_ENUM. This
may result in side-effect to DMIC based record usecases.
Update the RDAC2 MUX define to use correct widget.

Change-Id: Ia87200700118439e1c9dee4f79e6049729c4a74f
Signed-off-by: Laxminath Kasam <lkasam@codeaurora.org>