panthor: save task pid and comm in panthor_group

panthor: save task pid and comm in panthor_group

We would like to report them on gpu errors.

We choose to save the info on panthor_group_create rather than on
panthor_open because, when the two differ, we are more interested in the
task that created the group.

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250718063816.1452123-3-olvaffe@gmail.com