ARM: dts: sun8i: Add Allwinner A83T dtsi

Allwinner A83T is new octa-core cortex-a7 SOC.
This adds the basic dtsi, the clocks differs from
earlier sun8i SOCs.

Signed-off-by: Vishnu Patekar <vishnupatekar0510@gmail.com>
[Maxime: Removed empty chosen node]
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>