video: fbdev: pxafb: Add support for lcd-supply regulator

Optionally obtain a lcd-supply regulator during probe and use it in
__pxafb_lcd_power() to switch the power supply of LCD panels.

This helps boards booted from DT to control such voltages without
callbacks.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
diff --git a/drivers/video/fbdev/pxafb.h b/drivers/video/fbdev/pxafb.h
index 5dc414e..b641289 100644
--- a/drivers/video/fbdev/pxafb.h
+++ b/drivers/video/fbdev/pxafb.h
@@ -165,6 +165,9 @@ struct pxafb_info {
 	struct notifier_block	freq_policy;
 #endif
 
+	struct regulator *lcd_supply;
+	bool lcd_supply_enabled;
+
 	void (*lcd_power)(int, struct fb_var_screeninfo *);
 	void (*backlight_power)(int);