mm/gup_test: fix ioctl fail for compat task

mm/gup_test: fix ioctl fail for compat task

When tools/testing/selftests/mm/gup_test.c is compiled as 32bit, then run
on arm64 kernel, it reports "ioctl: Inappropriate ioctl for device".

Fix it by filling compat_ioctl in gup_test_fops

Link: https://lkml.kernel.org/r/20230526022125.175728-1-haibo.li@mediatek.com
Signed-off-by: Haibo Li <haibo.li@mediatek.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>