ASoC: msm8x16: Add channel config for Mi2S RX path

MSM8916 uses Mono Speaker and hence hardcoding of
channel needs to be fixed for Speaker path. A
hardware params fixup function is added for speaker
path to set the number of channels to one.

CRs-Fixed: 651438
Change-Id: Ie64c3b3919d0c12ba5d77b09a05bb0b3a6e262f8
Signed-off-by: Asish Bhattacharya <asishb@codeaurora.org>