drm/panthor: Introduce panthor_pwr API and power control framework

drm/panthor: Introduce panthor_pwr API and power control framework

Add the new panthor_pwr module, which provides basic power control
management for Mali-G1 GPUs. The initial implementation includes
infrastructure for initializing the PWR_CONTROL block, requesting and
handling its IRQ, and checking for PWR_CONTROL support based on GPU
architecture.

The patch also integrates panthor_pwr with the device lifecycle (init,
suspend, resume, and unplug) through the new API functions. It also
registers the IRQ handler under the 'gpu' IRQ as the PWR_CONTROL block
is located within the GPU_CONTROL block.

Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Karunika Choo <karunika.choo@arm.com>
Link: https://patch.msgid.link/20251125125548.3282320-4-karunika.choo@arm.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>