ARM: OMAP: Remove CONFIG_OMAP_MCBSP references

The McBSP driver stack has been moved to ASoC. The CONFIG_OMAP_MCBSP will
be removed since the CONFIG_SND_OMAP_SOC_MCBSP will trigger to build the
McBSP (audio) drivers.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Liam Girdwood <lrg@ti.com>