clk: sunxi: Add Allwinner A10/A20 CLK driver

Add initial clock driver for Allwinner A10/A20.

- Implement USB ahb and USB clocks via ccu_clk_gate table
  for A10/A20, so it can accessed in common clk enable and
  disable functions from clk_sunxi.c
- Implement USB resets via ccu_reset table for A10/A20,
  so it can accessed in common reset deassert and assert
  functions from reset-sunxi.c

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