drm/panfrost: Add missing _fini() calls in panfrost_device_fini()

panfrost_{job,mmu,gpu,reset}_fini() were missing.

Fixes: f3ba9122 ("drm/panfrost: Add initial panfrost driver")
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190513081734.911-1-boris.brezillon@collabora.com