ASoC: ti: davinci-mcasp: remove redundant assignment to variable ret

The assignment to ret is redundant as it is not used in the error
return path and hence can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20200210092423.327499-1-colin.king@canonical.com


Signed-off-by: Mark Brown <broonie@kernel.org>