ASoC: max9867: silence and array overflow warning

Smatch complains that we might reach the end of this loop without
finding what we're looking for leading to a buffer overflow.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>