pmdomain: airoha: Add Airoha CPU PM Domain support

Add Airoha CPU PM Domain support to control frequency and power of CPU
present on Airoha EN7581 SoC.

Frequency and power can be controlled with the use of the SMC command by
passing the performance state. The driver also expose a read-only clock
that expose the current CPU frequency with SMC command.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Link: https://lore.kernel.org/r/20250109131313.32317-1-ansuelsmth@gmail.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>