configs: sdm660: Fix sidetone mute during voice call

Update sidetone mixer controls to avoid sidetone loopback mute
during voice call on headset and handset.

CRs-Fixed: 2020173
Change-Id: Ib55d1842ffdfee704bfbb4d718978c4a085eaf0e
Signed-off-by: Laxminath Kasam <lkasam@codeaurora.org>