ASoC: Add TWS+ mono mode support

Add support to enable mono mode when one TWS+ earbud is
connected. Change the encoder config when device switches from two
earbuds to single earbud.

CRs-Fixed: 2341876
Change-Id: I880aa6a2767d88e99be2d80afff0e5fbec94b8a4
Signed-off-by: Manisha Agarwal <maniagar@codeaurora.org>