OMAPDSS: fix warnings if CONFIG_PM_RUNTIME=n

If runtime PM is not enabled in the kernel config, pm_runtime_get_sync()
will always return 1 and pm_runtime_put_sync() will always return
-ENOSYS. pm_runtime_get_sync() returning 1 presents no problem to the
driver, but -ENOSYS from pm_runtime_put_sync() causes the driver to
print a warning.

One option would be to ignore errors returned by pm_runtime_put_sync()
totally, as they only say that the call was unable to put the hardware
into suspend mode.

However, I chose to ignore the returned -ENOSYS explicitly, and print a
warning for other errors, as I think we should get notified if the HW
failed to go to suspend properly.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Jassi Brar <jaswinder.singh@linaro.org>
Cc: Grazvydas Ignotas <notasas@gmail.com>
diff --git a/drivers/video/omap2/dss/dss.c b/drivers/video/omap2/dss/dss.c
index 7706323..d2b5719 100644
--- a/drivers/video/omap2/dss/dss.c
+++ b/drivers/video/omap2/dss/dss.c
@@ -731,7 +731,7 @@
 	DSSDBG("dss_runtime_put\n");
 
 	r = pm_runtime_put_sync(&dss.pdev->dev);
-	WARN_ON(r < 0 && r != -EBUSY);
+	WARN_ON(r < 0 && r != -ENOSYS && r != -EBUSY);
 }
 
 /* DEBUGFS */