HID: input: add mapping for keyboard Brightness Up/Down/Toggle keys

According to HUTRR73 usages 0x79, 0x7a and 0x7c from the consumer page
correspond to Brightness Up/Down/Toggle keys, so let's add the mappings.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/hid/hid-input.c

@@ -900,6 +900,10 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
 		case 0x074: map_key_clear(KEY_BRIGHTNESS_MAX);		break;
 		case 0x075: map_key_clear(KEY_BRIGHTNESS_AUTO);		break;
 
+		case 0x079: map_key_clear(KEY_KBDILLUMUP);	break;
+		case 0x07a: map_key_clear(KEY_KBDILLUMDOWN);	break;
+		case 0x07c: map_key_clear(KEY_KBDILLUMTOGGLE);	break;
+
 		case 0x082: map_key_clear(KEY_VIDEO_NEXT);	break;
 		case 0x083: map_key_clear(KEY_LAST);		break;
 		case 0x084: map_key_clear(KEY_ENTER);		break;