pmdomain: sunxi: add H6 PRCM PPU driver

pmdomain: sunxi: add H6 PRCM PPU driver

The Allwinner Power Reset Clock Management (RPCM) block contains a few
bits that control some power domains. The most prominent one is the one
for the Mali GPU. On the Allwinner H6 this domain is enabled at reset, so
we didn't care about it so far, but the H616 defaults to it being disabled.

Add a power domain driver for those bits. Some BSP code snippets and
some spare documentation describe three bits, slightly different between
the H6 and H616, so add three power domains for each SoC, connected to
their compatible string.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20250416224839.9840-3-andre.przywara@arm.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>