drm/panthor: Add driver IOCTL for setting BO labels

Allow UM to label a BO for which it possesses a DRM handle.

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250423021238.1639175-3-adrian.larumbe@collabora.com


Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>