ASoC: davinci-mcasp: Fix overwriting of ahclkx

The mcasp davinci_mcasp_set_dai_fmt function was overriding ahclkx
input/output status that had already been set by the
davinci_mcasp_set_sysclk function. This commit removes clearing
of the ahclkx input/output status from davinci_mcasp_set_dai_fmt.

Signed-off-by: Jim Lodes <jim.lodes@garmin.com>
Signed-off-by: J.D. Schroeder <jay.schroeder@garmin.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>