HID: core: add two new usages for digitizer

On Feb 17, 2014, two new usages are approved to HID usage Table 18 -
Digitizer Page:

5A	Secondary Barrel Switch		MC	16.4
5B	Transducer Serial Number	SV	16.3.1

This patch adds relevant definitions to hid/input. It also removes
outdated comments in hid.h.

Signed-off-by: Ping Cheng <pingc@wacom.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-debug.c

@@ -165,6 +165,8 @@ static const struct hid_usage_entry hid_usage_table[] = {
     {0, 0x53, "DeviceIndex"},
     {0, 0x54, "ContactCount"},
     {0, 0x55, "ContactMaximumNumber"},
+    {0, 0x5A, "SecondaryBarrelSwitch"},
+    {0, 0x5B, "TransducerSerialNumber"},
   { 15, 0, "PhysicalInterfaceDevice" },
     {0, 0x00, "Undefined"},
     {0, 0x01, "Physical_Interface_Device"},

drivers/hid/hid-input.c

@@ -684,9 +684,14 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
 			break;
 
 		case 0x46: /* TabletPick */
+		case 0x5a: /* SecondaryBarrelSwitch */
 			map_key_clear(BTN_STYLUS2);
 			break;
 
+		case 0x5b: /* TransducerSerialNumber */
+			set_bit(MSC_SERIAL, input->mscbit);
+			break;
+
 		default:  goto unknown;
 		}
 		break;