HID: wacom: Fix pad button range for CINTIQ_COMPANION_2

Commit c7f0522a incorrectly constructs the 'buttons' variable for the
CINTIQ_COMPANION_2 case. The high nybble of data[2] is shifted four
bits too far, leaving the bits associated with BTN_7 through BTN_A
unset.
Signed-off-by: NJason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/hid/wacom_wac.c

@@ -516,7 +516,7 @@ static int wacom_intuos_pad(struct wacom_wac *wacom)
 		 * d-pad down   -> data[4] & 0x80
 		 * d-pad center -> data[3] & 0x01
 		 */
-		buttons = ((data[2] & 0xF0) << 7) |
+		buttons = ((data[2] >> 4) << 7) |
 		          ((data[1] & 0x04) << 6) |
 		          ((data[2] & 0x0F) << 2) |
 		          (data[1] & 0x03);