When trying to boot via USB on i.MX8MN it is necessary to specify
the U-Boot environment location, otherwise the boot process simply
hangs.
Specify the environment location when booting from USB.
Tested on a imx8mn-evk.
Suggested-by: Michael Nazzareno Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Fabio Estevam <festevam@denx.de>
Tested-By: Tim Harvey <tharvey@gateworks.com>