drm/panfrost: Introduce uAPI for JM context creation

drm/panfrost: Introduce uAPI for JM context creation

The new uAPI lets user space query the KM driver for the available
priorities a job can be given at submit time. These are managed through
the notion of a context, for which we also provide new creation and
destruction ioctls.

Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250917191859.500279-2-adrian.larumbe@collabora.com