alienware-wmi: Update WMAX brightness method limit to 15

This more closely reflects what the hardware can actually support.

Signed-off-by: Mario Limonciello <[e-mail]>
Signed-off-by: Matthew Garrett <[e-mail]>

drivers/platform/x86/alienware-wmi.c

···
 	char *name;
 
 	if (interface == WMAX) {
-		global_led.max_brightness = 100;
 		lighting_control_state = WMAX_RUNNING;
 	} else if (interface == LEGACY) {
-		global_led.max_brightness = 0x0F;
 		lighting_control_state = LEGACY_RUNNING;
 	}
+	global_led.max_brightness = 0x0F;
 	global_brightness = global_led.max_brightness;
 
 	/*