macintosh/via-pmu-backlight: Use backlight power constants

Replace FB_BLANK_ constants with their counterparts from the
backlight subsystem. The values are identical, so there's no
change in functionality or semantics.

via-pmu-backlight.c already includes backlight.h where the
BACKLIGHT constants are defined.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240731130720.1148872-3-tzimmermann@suse.de

drivers/macintosh/via-pmu-backlight.c

@@ -178,7 +178,7 @@ void __init pmu_backlight_init(void)
 	}
 
 	bd->props.brightness = level;
-	bd->props.power = FB_BLANK_UNBLANK;
+	bd->props.power = BACKLIGHT_POWER_ON;
 	backlight_update_status(bd);
 
 	printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);