Add mod % 2 to allow dev_index to work with WSA2 Macro.
Also fix issues associated with incorrect parameter
checking of dev_index leading to potential array index
out-of-bounds issues.
Change WSA MODE mixer control to be SOC_SINGLE_EXT for
extra parameter validation.
Change-Id: I030ee64d87fa60c6b44feebf5ccb1265f4291cc1
Signed-off-by: Matthew Rice <quic_mrice@quicinc.com>