ARM: OMAP: musb: Adding support for ti81xx

Added musb support for ti81xx platform which has two instances of musb
interface and uses CPPI4.1 DMA. The current patch set adds support for
single instance and in PIO mode only.

Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Ravi Babu <ravibabu@ti.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>