sun6i: ehci: Add sun6i ehci support

Add support for the 2 ehci controllers found on the sun6i (A31) soc.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Acked-by: Marek Vasut <marex@denx.de>