acer-wmi: Fix backlight on AMW0 (V1) laptops

There is some leftover cruft from the old quirk infrastructure that causes
us to be unable to set the backlight on older laptops.
Signed-off-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/misc/acer-wmi.c

@@ -428,10 +428,8 @@ static acpi_status AMW0_set_u32(u32 value, u32 cap, struct wmi_interface *iface)
 		if (value > max_brightness)
 			return AE_BAD_PARAMETER;
 		switch (quirks->brightness) {
-		case 1:
-			return ec_write(0x83, value);
 		default:
-			return AE_BAD_ADDRESS;
+			return ec_write(0x83, value);
 			break;
 		}
 	default: