clk: sunxi: Add Allwinner H6 CLK driver

clk: sunxi: Add Allwinner H6 CLK driver

Add initial clock driver for Allwinner H6.

- Implement UART bus clocks via ccu_clk_gate table for
  H6, so it can accessed in common clk enable and disable
  functions from clk_sunxi.c
- Implement UART bus resets via ccu_reset table for H6,
  so it can accessed in common reset deassert and assert
  functions from reset-sunxi.c

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>