Currently AoC always use 3ch in voice usecase
rather than using mic MAX microphone as ch count.
We have changed mechanism to mapping pdm mask on
voice usecase in AUD_PDM.
Modify the mask to map voice request.
Bug: 316603846
Change-Id: Idf92d1da0df632c6410d30147725857e55cef70b
Signed-off-by: yixuanjiang <yixuanjiang@google.com>