drm/panthor: Call panthor_gpu_coherency_init() after PM resume()

drm/panthor: Call panthor_gpu_coherency_init() after PM resume()

When the device is coherent, panthor_gpu_coherency_init() will read
GPU_COHERENCY_FEATURES to make sure the GPU supports the ACE-Lite
coherency protocol, which will fail if the clocks/power-domains are
not enabled when the read is done. Move the
panthor_gpu_coherency_init() call after the device has been resumed
to prevent that.

Changes in v2:
- Add Liviu's R-b

Changes in v3:
- Add Steve's R-b

Fixes: dd7db8d911a1 ("drm/panthor: Explicitly set the coherency mode")
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250404080933.2912674-3-boris.brezillon@collabora.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>