OMAPDSS: adopt pinctrl support

Update omapdss driver to set the state of the pins to:
- "default on resume
- "sleep" on suspend

By optionally putting the pins into sleep state in the suspend callback
we can accomplish two things.
- minimize current leakage from pins and thus save power,
- prevent the IP from driving pins output in an uncontrolled manner,
which may happen if the power domain drops the domain regulator.
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/fbdev/omap2/dss/dss.c

@@ -1264,12 +1264,18 @@ static int dss_runtime_suspend(struct device *dev)
 {
 	dss_save_context();
 	dss_set_min_bus_tput(dev, 0);
+
+	pinctrl_pm_select_sleep_state(dev);
+
 	return 0;
 }
 
 static int dss_runtime_resume(struct device *dev)
 {
 	int r;
+
+	pinctrl_pm_select_default_state(dev);
+
 	/*
 	 * Set an arbitrarily high tput request to ensure OPP100.
 	 * What we should really do is to make a request to stay in OPP100,