ASoC: msm: Ignore unexpected events from dsp

If dsp responds with an expected event, audio driver
should ignore the response and continue. Change removes
the BUG_ON and handles the error gracefully.

CRs-fixed: 495205
Change-Id: I3051a90574b36061726c691672ec28fcc8976193
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>