sunxi: A64: enable USB support

Mostly by adding MACH_SUN50I to some existing #ifdefs enable support
for the the HCI0 USB host controller on the A64.
Fix up some minor 64-bit hiccups on the way.
Add the bare minimum DT bits to the A64 .dtsi and enable the controllers
and the PHY on the Pine64.
This is limited to the first USB controller at the moment, which is
connected to the lower USB socket on the Pine64 board.
[Andre: remove unneeded defines, enable OHCI, add commit message]

Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>