sun5i: add USB EHCI settings

Specific USB EHCI settings to be set for sun5i if CONFIG_USB_EHCI is enabled.

Note we don't specify default VBUS gpio pins for sun5i since they vary too
much from board to board.

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