PM: runtime: Stop checking pm_runtime_barrier() return code

Apparently this test is the only code that checks the return code from
pm_runtime_barrier(), and it turns out that's for good reason -- it's
inherently racy, and a bad idea. We're going to make
pm_runtime_barrier() return void, so prepare for that by dropping any
return code checks.

This resolves some test failures seen like the following:

[   34.559694]     # pm_runtime_error_test: EXPECTATION FAILED at drivers/base/power/runtime-test.c:177
[   34.559694]     Expected 1 == pm_runtime_barrier(dev), but
[   34.559694]         pm_runtime_barrier(dev) == 0 (0x0)
[   34.563604]     # pm_runtime_error_test: pass:0 fail:1 skip:0 total:1

Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/lkml/93259f2b-7017-4096-a31b-cabbf6152e9b@roeck-us.net/
Signed-off-by: Brian Norris <briannorris@chromium.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://patch.msgid.link/20251202193129.1411419-1-briannorris@chromium.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: computersforpeace

drivers/base/power/runtime-test.c

@@ -37,10 +37,6 @@ static void pm_runtime_already_suspended_test(struct kunit *test)
 	pm_runtime_enable(dev);
 	KUNIT_EXPECT_TRUE(test, pm_runtime_suspended(dev));
 
-	pm_runtime_get_noresume(dev);
-	KUNIT_EXPECT_EQ(test, 0, pm_runtime_barrier(dev)); /* no wakeup needed */
-	pm_runtime_put(dev);
-
 	pm_runtime_get_noresume(dev);
 	KUNIT_EXPECT_EQ(test, 1, pm_runtime_put_sync(dev));
 
@@ -174,7 +170,7 @@ static void pm_runtime_error_test(struct kunit *test)
 	KUNIT_EXPECT_TRUE(test, pm_runtime_suspended(dev));
 
 	KUNIT_EXPECT_EQ(test, 0, pm_runtime_get(dev));
-	KUNIT_EXPECT_EQ(test, 1, pm_runtime_barrier(dev)); /* resume was pending */
+	pm_runtime_barrier(dev);
 	pm_runtime_put(dev);
 	pm_runtime_suspend(dev); /* flush the put(), to suspend */
 	KUNIT_EXPECT_TRUE(test, pm_runtime_suspended(dev));
@@ -225,7 +221,7 @@ static void pm_runtime_probe_active_test(struct kunit *test)
 	KUNIT_EXPECT_TRUE(test, pm_runtime_active(dev));
 
 	/* Nothing to flush. We stay active. */
-	KUNIT_EXPECT_EQ(test, 0, pm_runtime_barrier(dev));
+	pm_runtime_barrier(dev);
 	KUNIT_EXPECT_TRUE(test, pm_runtime_active(dev));
 
 	/* Ask for idle? Now we suspend. */