selftests/perf_events: Fix spelling mistake "sycnhronize" -> "synchronize"

There is a spelling mistake in an error message. Fix it.

Link: https://lore.kernel.org/r/20240327110649.283925-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Kyle Huey <khuey@kylehuey.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/perf_events/watermark_signal.c

@@ -75,7 +75,7 @@ TEST(watermark_signal)
 	if (waitpid(child, &child_status, WSTOPPED) != child ||
 	    !(WIFSTOPPED(child_status) && WSTOPSIG(child_status) == SIGSTOP)) {
 		fprintf(stderr,
-			"failed to sycnhronize with child errno=%d status=%x\n",
+			"failed to synchronize with child errno=%d status=%x\n",
 			errno,
 			child_status);
 		goto cleanup;