ASoC: fsl_micfil: Fix unused assignment in fsl_set_clock_params()

Delete unused initialized value of 'ret', because it will
be assigned by the function fsl_micfil_set_mclk_rate().

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20200518110040.18036-1-tangbin@cmss.chinamobile.com


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