sunxi: clk: add MMC gates/resets

Add the MMC clock gates and reset bits for all the Allwinner SoCs.
This allows them to be used by the MMC driver.

We don't advertise the mod clock yet, as this is still handled by the
MMC driver.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
[jagan: add V3S, A80 gates/resets]
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>