Add initial clock driver for Allwinner A80.

- Implement UART bus clocks via ccu_clk_gate table for
  A80, so it can accessed in common clk enable and disable
  functions from clk_sunxi.c
- Implement UART bus resets via ccu_reset table for A80,
  so it can accessed in common reset deassert and assert
  functions from reset-sunxi.c

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>