ASoC: apq8084: Fix voice call over BTSCO wideband

Voice call over BTSCO wideband does not work because of sample rate
mismatch. Userspace sets sample rate as string which is passed to
kernel as index. So sample rate checks should be based on index in kernel.

Change-Id: Iaee4ad5f91478173034068c4f2a184981b0fd394
Signed-off-by: Vidyakumar Athota <vathota@codeaurora.org>