HID: support for Kensington slimblade device

0x47d/0x2041 device sends two extra buttons in 0xff00 usage
page and therefore requires special handling.

Reported-by: Jason Noble <nobleja@polezero.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 9e83ca4..7270ccc 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -274,6 +274,9 @@
 #define USB_DEVICE_ID_LD_POWERCONTROL	0x2030
 #define USB_DEVICE_ID_LD_MACHINETEST	0x2040
 
+#define USB_VENDOR_ID_KENSINGTON	0x047d
+#define USB_DEVICE_ID_KS_SLIMBLADE	0x2041
+
 #define USB_VENDOR_ID_LOGITECH		0x046d
 #define USB_DEVICE_ID_LOGITECH_RECEIVER	0xc101
 #define USB_DEVICE_ID_LOGITECH_HARMONY_FIRST  0xc110