sunxi: H3: fix non working console on uart2

Fix non working console on uart2, that seems releated to both
Allwinner H2+ and H3.

Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
[Andre: remove H2+, rearrange pin setup order]
Signed-off-by: Andre Przywara <andre.przywara@arm.com>