hal: Enable support for multichannel tunnel USB.

-Update platform_check_codec api to enable support for multichannel
tunnel USB
-Update condition to check if voice call is active on a specific backend
then only force configure it
-Update the check to ensure that offload callback is triggered only for
non blocking writes.

Change-Id: I0dbd61c28b24cdba22f63b0e014eb7c362e2df34