PMU is the power management unit and GRF is the general register file. Both
are heavily used in U-Boot. Add header files with register definitions.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Kever Yang <kever.yang@rock-chips.com>
