imx8mp-evk: Add USB0 OTG support

Add USB0 OTG support.

Currently, the USB0 OTG nodes are not enabled in the Linux kernel
devicetree.

For this reason, enable the USB0 OTG nodes inside imx8mp-evk-u-boot.dtsi
for now.

Also select several useful options such as USB gadget and fastboot.

Tested by running "ums 0 mmc 2".

Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Marek Vasut <marex@denx.de>