selftests/mm: sigbus-wp test requires UFFD_FEATURE_WP_HUGETLBFS_SHMEM

The sigbus-wp test requires the UFFD_FEATURE_WP_HUGETLBFS_SHMEM flag for
shmem and hugetlb targets.  Otherwise it is not backwards compatible with
kernels <5.19 and fails with EINVAL.

Link: https://lkml.kernel.org/r/20240321232023.2064975-1-edliaw@google.com
Fixes: 73c1ea93 ("selftests/mm: move uffd sig/events tests into uffd unit tests")
Signed-off-by: Edward Liaw <edliaw@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Peter Xu <peterx@redhat.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/testing/selftests/mm/uffd-unit-tests.c

@@ -1427,7 +1427,8 @@ uffd_test_case_t uffd_tests[] = {
 		.uffd_fn = uffd_sigbus_wp_test,
 		.mem_targets = MEM_ALL,
 		.uffd_feature_required = UFFD_FEATURE_SIGBUS |
-		UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_PAGEFAULT_FLAG_WP,
+		UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_PAGEFAULT_FLAG_WP |
+		UFFD_FEATURE_WP_HUGETLBFS_SHMEM,
 	},
 	{
 		.name = "events",