HID: elecom: add support for EX-G M-XGL20DLBK wireless mouse

Enables three buttons (Fn1, Fn2, and Fn3) on the ELECOM M-XGL20DLBK
wireless mouse.

While this mouse is EX-G brand, report descriptor is a bit different
from EX-G trackball mouse. To enable extra buttons, report should be
rewritten in a similar way to trackballs, but with different position
parameters.

Signed-off-by: YOSHIOKA Takuma <lo48576@hard-wi.red>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index f170fea..7fcbd3c 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -390,6 +390,7 @@
 
 #define USB_VENDOR_ID_ELECOM		0x056e
 #define USB_DEVICE_ID_ELECOM_BM084	0x0061
+#define USB_DEVICE_ID_ELECOM_M_XGL20DLBK	0x00e6
 #define USB_DEVICE_ID_ELECOM_M_XT3URBK	0x00fb
 #define USB_DEVICE_ID_ELECOM_M_XT3DRBK	0x00fc
 #define USB_DEVICE_ID_ELECOM_M_XT4DRBK	0x00fd