fbdev: sh_mobile_lcdc: Store the backlight brightness internally

There's no need to query the hardware for the currenty brightness value
through a platform data callback when we can cache the value internally
in the LCDC driver.

Signed-off-by: Laurent Pinchart <[e-mail]>

drivers/video/sh_mobile_lcdcfb.c

···
 	    bdev->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
 		brightness = 0;
 
+	ch->bl_brightness = brightness;
 	return ch->cfg->bl_info.set_brightness(brightness);
 }
 
···
 {
 	struct sh_mobile_lcdc_chan *ch = bl_get_data(bdev);
 
-	return ch->cfg->bl_info.get_brightness();
+	return ch->bl_brightness;
 }
 
 static int sh_mobile_lcdc_check_fb(struct backlight_device *bdev,

drivers/video/sh_mobile_lcdcfb.h

···
 
 	/* Backlight */
 	struct backlight_device *bl;
+	unsigned int bl_brightness;
 
 	/* FB */
 	struct fb_info *info;