HID: hid-input: Add eraser usage to hidinput_configure_usage

Some tablets report eraser usage to indicate the eraser tool tip
is touching the surface. But, hidinput_configure_usage didn't
support the usage, which led it falls into default as ABS_MISC.

Signed-off-by: Ping Cheng <ping.cheng@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 199f6a0..04d01b5 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -797,6 +797,15 @@
 			map_key_clear(BTN_STYLUS);
 			break;
 
+		case 0x45: /* ERASER */
+			/*
+			 * This event is reported when eraser tip touches the surface.
+			 * Actual eraser (BTN_TOOL_RUBBER) is set by Invert usage when
+			 * tool gets in proximity.
+			 */
+			map_key_clear(BTN_TOUCH);
+			break;
+
 		case 0x46: /* TabletPick */
 		case 0x5a: /* SecondaryBarrelSwitch */
 			map_key_clear(BTN_STYLUS2);