usb: musb: Use is_cppi_enabled() and tusb_dma_omap() instead of the ifdef

This patch makes use of the two function is_cppi_enabled() and
tusb_dma_omap() instead of the ifdef for the proper DMA implementation
setup code. It basically shifts the code right by one indention level
and adds a few line breaks once the chars are crossed.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>