clk: Add Allwinner A64 CLK driver

Add initial clock driver for Allwinner A64.

Implement USB clock enable and disable functions for
OHCI, EHCI, OTG and USBPHY gate and clock registers
via ccu clk gate table.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>