This adds support for the A20 Hummingbird:
http://www.merrii.com/en/pla_d.asp?id=171

This patch enable most on-board peripherals supported on current kernel,
such as uart, i2c, spi, pwm, ohci/ehci, gmac and mmc.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NWills Wang <wills.wang.open@gmail.com>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>