readahead01: pass on pidfd

Linux kernel added pidfs via commit b5683a37c881 in v6.9-rc1
release. This patchset ignores readahead request instead of
returning EINVAL, so mark the test pass.

https://lkml.iu.edu/hypermail/linux/kernel/2403.2/00762.html

Signed-off-by: Murphy Zhou <[email protected]>
Reviewed-by: Cyril Hrubis <[email protected]>

testcases/kernel/syscalls/readahead/readahead01.c

@@ -53,6 +53,7 @@ static void test_invalid_fd(struct tst_fd *fd)
 	case TST_FD_MEMFD:
 	case TST_FD_MEMFD_SECRET:
 	case TST_FD_PROC_MAPS:
+	case TST_FD_PIDFD:
 		return;
 	default:
 		break;