selftests/pidfd_test: Remove the erroneous ','

Remove the erroneous ',', otherwise it might result in wrong output
and report:
 ...
 Bail out! (errno %d)
  test: Unexpected epoll_wait result (c=4208480, events=2)
 ...

Fixes: 740378dc ("pidfd: add polling selftests")
Signed-off-by: Zhao Gongyi <zhaogongyi@huawei.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/pidfd/pidfd_test.c

@@ -413,7 +413,7 @@ static void poll_pidfd(const char *test_name, int pidfd)
 
 	c = epoll_wait(epoll_fd, events, MAX_EVENTS, 5000);
 	if (c != 1 || !(events[0].events & EPOLLIN))
-		ksft_exit_fail_msg("%s test: Unexpected epoll_wait result (c=%d, events=%x) ",
+		ksft_exit_fail_msg("%s test: Unexpected epoll_wait result (c=%d, events=%x) "
 				   "(errno %d)\n",
 				   test_name, c, events[0].events, errno);