ARM64: dts: amlogic: Add hiu and periphs buses

Add two new buses in the DTS: hiu and periphs buses.
In the Amlogic S905/GXBB SoC several devices (clock / eth / pin
controllers, etc...) are mapped under these two buses. Add them in the
DT before starting to add new devices.

Signed-off-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>