pico-imx6ul: Add USB Host support

Add USB host support.

Tested by connecting a USB pen drive:

=> usb start
starting USB...
USB0:   Port not available.
USB1:   USB EHCI 1.00
scanning bus 1 for devices... 2 USB Device(s) found
       scanning usb for storage devices... 1 Storage Device(s) found

Signed-off-by: Vanessa Maegima <vanessa.maegima@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
2 files changed