arm64: dts: allwinner: h616: Add Mali GPU node

arm64: dts: allwinner: h616: Add Mali GPU node

The Allwinner H616 SoC contains a Mali-G31 MP2 GPU, which is of the Mali
Bifrost family. There is a power domain specifically for that GPU, which
needs to be enabled to make use of the it.

Add the DT nodes for those two devices, and link them together through
the "power-domains" property.
Any board wishing to use the GPU would need to enable the GPU node and
specify the "mali-supply" regulator.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://patch.msgid.link/20250416224839.9840-4-andre.przywara@arm.com
Signed-off-by: Chen-Yu Tsai <wens@csie.org>