drm/panthor: Add 64-bit and poll register accessors

drm/panthor: Add 64-bit and poll register accessors

This patch adds 64-bit register accessors to simplify register access in
Panthor. It also adds 32-bit and 64-bit variants for read_poll_timeout.

This patch also updates Panthor to use the new 64-bit accessors and poll
functions.

Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Karunika Choo <karunika.choo@arm.com>
Link: https://lore.kernel.org/r/20250606101835.41840-2-boris.brezillon@collabora.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>