ASoC: omap-mcbsp: Remove restrictive checks for cpu type

Current checks for cpu type were too restrictive leading
to failures for other silicons in same family.

The problem was found while testing audio playback on
AM37x and AM35x processors. But should exist on OMAP36xx
as well.

Signed-off-by: Sanjeev Premi <premi@ti.com>
cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
cc: Liam Girdwood <lrg@ti.com>
cc: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@ti.com>