ASoC: omap-mcbsp: Rename omap_mcbsp_sysfs_remove() to omap_mcbsp_cleanup()

The function will do more then removing the sysfs files in the future.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>