backlight: aat2870-backlight: Use blacklight power constants

Replace FB_BLANK_ constants with their counterparts from the
backlight subsystem. The values are identical, so there's no
change in functionality.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20240624152033.25016-3-tzimmermann@suse.deSigned-off-by: Lee Jones <lee@kernel.org>

drivers/video/backlight/aat2870_bl.c

@@ -156,7 +156,7 @@ static int aat2870_bl_probe(struct platform_device *pdev)
 		bd->props.max_brightness = 255;
 
 	aat2870_bl->brightness = 0;
-	bd->props.power = FB_BLANK_UNBLANK;
+	bd->props.power = BACKLIGHT_POWER_ON;
 	bd->props.brightness = bd->props.max_brightness;
 
 	ret = aat2870_bl_update_status(bd);
@@ -176,7 +176,7 @@ static void aat2870_bl_remove(struct platform_device *pdev)
 	struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
 	struct backlight_device *bd = aat2870_bl->bd;
 
-	bd->props.power = FB_BLANK_POWERDOWN;
+	bd->props.power = BACKLIGHT_POWER_OFF;
 	bd->props.brightness = 0;
 	backlight_update_status(bd);
 }