Some boards with the Allwinner F1C100s family SoCs use UART1 for its
debug UART, so define the pins for the SPL and the pinmux name and mux
value for U-Boot proper.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>