verdin-imx8mm, verdin-imx8mp: Fix default systemd console output

systemd prints its messages on the last console= statement that it finds
in the kernel arguments. The current ordering sends the systemd messages
to tty1, by default this is the display.

Ensure that systemd sends its messages to the default UART, reorder the
console= statements accordingly.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Reviewed-by: Stefano Babic <sbabic@denx.de>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>