drm/panfrost: Drop the pfdev argument passed to panfrost_exception_name()

Currently unused. We'll add it back if we need per-GPU definitions.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210630062751.2832545-6-boris.brezillon@collabora.com