board: toradex: verdin-imx8mp: enable usb device and fastboot support

Enable USB device and fastboot support which may be used to load the
Toradex Easy Installer FIT image.

While at it also enable USB mass storage aka UMS support.

Note that the i.MX 8M Plus recovery mode support is based on the USB
boot stage of the BOOTROM and does NOT require USB SDP SPL aka serial
downloader support.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Fabio Estevam <festevam@denx.de>