- DMA tx and rx maps for usb channels are set to be configured at
  runtime
- GPIO configurations for usb are added
- MUSB is enabled with soc specific base address, irq and dma
  configurations
Signed-off-by: Mian Yousaf Kaukab <mian-yousaf.kaukab@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>