dt-bindings: power: Add R8A779H0 V4M SYSC power domain definitions

Add power domain indices for R-Car V4M (R8A779H0).

The current version is imported from:
https://lore.kernel.org/linux-renesas-soc/c5cbef71178cada761e9da7bcbb6f21334f93ef8.1706194617.git.geert+renesas@glider.be/



Signed-off-by: Duy Nguyen <duy.nguyen.rh@renesas.com>
Signed-off-by: Hai Pham <hai.pham.ud@renesas.com>