ASoC: ti: omap-mcbsp: duplicate sysfs error

Convert to managed versions of sysfs and clk allocation to simplify
unbinding and error handling in probe.  Managed sysfs node
creation specifically addresses the following error seen the second time
probe is attempted after sdma_pcm_platform_register() previously requsted
probe deferral:

sysfs: cannot create duplicate filename '/devices/platform/68000000.ocp/49022000.mcbsp/max_tx_thres'

Signed-off-by: David Owens <dowens@precisionplanting.com>
Link: https://lore.kernel.org/r/20220620183744.3176557-1-dowens@precisionplanting.com
Signed-off-by: Mark Brown <broonie@kernel.org>