selftests/clone3: fix number of tests in ksft_set_plan

Commit 515bddf0 ("selftests/clone3: test clone3 with CLONE_NEWTIME")
added an additional test, so the number passed to ksft_set_plan needs to
be bumped accordingly.

Also use ksft_finished() to print results and exit. This will catch future
mismatches between ksft_set_plan() and the number of tests being run.

Fixes: 515bddf0 ("selftests/clone3: test clone3 with CLONE_NEWTIME")
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

tools/testing/selftests/clone3/clone3.c

@@ -129,7 +129,7 @@ int main(int argc, char *argv[])
 	uid_t uid = getuid();
 
 	ksft_print_header();
-	ksft_set_plan(17);
+	ksft_set_plan(18);
 	test_clone3_supported();
 
 	/* Just a simple clone3() should return 0.*/
@@ -198,5 +198,5 @@ int main(int argc, char *argv[])
 	/* Do a clone3() in a new time namespace */
 	test_clone3(CLONE_NEWTIME, 0, 0, CLONE3_ARGS_NO_TEST);
 
-	return !ksft_get_fail_cnt() ? ksft_exit_pass() : ksft_exit_fail();
+	ksft_finished();
 }