drm/panthor: Add arch-specific panthor_hw binding

drm/panthor: Add arch-specific panthor_hw binding

This patch adds the framework for binding to a specific panthor_hw
structure based on the architecture major value parsed from the GPU_ID
register. This is in preparation of enabling architecture-specific
behaviours based on GPU_ID. As such, it also splits the GPU_ID register
read operation into its own helper function.

This framework allows a single panthor_hw structure to be shared across
multiple architectures should there be minimal changes between them via
the arch_min and arch_max field of the panthor_hw_entry structure,
instead of duplicating the structure across multiple architectures.

Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Karunika Choo <karunika.choo@arm.com>
Link: https://patch.msgid.link/20251125125548.3282320-2-karunika.choo@arm.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>