PM: runtime: clk: Fix clk_pm_runtime_get() error path

commit 64c7d7ea upstream.

clk_pm_runtime_get() assumes that the PM-runtime usage counter will
be dropped by pm_runtime_get_sync() on errors, which is not the case,
so PM-runtime references to devices acquired by the former are leaked
on errors returned by the latter.

Fix this by modifying clk_pm_runtime_get() to drop the reference if
pm_runtime_get_sync() returns an error.

Fixes: 9a34b453 clk: Add support for runtime PM
Cc: 4.15+ <stable@vger.kernel.org> # 4.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/clk/clk.c

@@ -101,7 +101,11 @@ static int clk_pm_runtime_get(struct clk_core *core)
 		return 0;
 
 	ret = pm_runtime_get_sync(core->dev);
-	return ret < 0 ? ret : 0;
+	if (ret < 0) {
+		pm_runtime_put_noidle(core->dev);
+		return ret;
+	}
+	return 0;
 }
 
 static void clk_pm_runtime_put(struct clk_core *core)