fbdev: nvidia: 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: Antonino Daplas <adaplas@gmail.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/video/fbdev/nvidia/nv_backlight.c

@@ -49,17 +49,11 @@ static int nvidia_bl_update_status(struct backlight_device *bd)
 {
 	struct nvidia_par *par = bl_get_data(bd);
 	u32 tmp_pcrt, tmp_pmc, fpcontrol;
-	int level;
+	int level = backlight_get_brightness(bd);
 
 	if (!par->FlatPanel)
 		return 0;
 
-	if (bd->props.power != FB_BLANK_UNBLANK ||
-	    bd->props.fb_blank != FB_BLANK_UNBLANK)
-		level = 0;
-	else
-		level = bd->props.brightness;
-
 	tmp_pmc = NV_RD32(par->PMC, 0x10F0) & 0x0000FFFF;
 	tmp_pcrt = NV_RD32(par->PCRTC0, 0x081C) & 0xFFFFFFFC;
 	fpcontrol = NV_RD32(par->PRAMDAC, 0x0848) & 0xCFFFFFCC;