fbdev: aty128fb: Use backlight helper

Instead of retrieving the backlight brightness in struct
backlight_properties manually, and then checking whether the backlight
should be on at all, use backlight_get_brightness() which does all
this and insulates this from future changes.
Signed-off-by: Stephen Kitt <steve@sk2.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/video/fbdev/aty/aty128fb.c

@@ -1766,12 +1766,10 @@ static int aty128_bl_update_status(struct backlight_device *bd)
 	unsigned int reg = aty_ld_le32(LVDS_GEN_CNTL);
 	int level;
 
-	if (bd->props.power != FB_BLANK_UNBLANK ||
-	    bd->props.fb_blank != FB_BLANK_UNBLANK ||
-	    !par->lcd_on)
+	if (!par->lcd_on)
 		level = 0;
 	else
-		level = bd->props.brightness;
+		level = backlight_get_brightness(bd);
 
 	reg |= LVDS_BL_MOD_EN | LVDS_BLON;
 	if (level > 0) {