HID: wacom: fix bit shift for Cintiq Companion 2

The bit indicating BTN_6 on this device is overshifted
by 2 bits, resulting in the incorrect button being
reported.

Also fix copy-paste mistake in comments.

Signed-off-by: Aaron Armstrong Skomra <[e-mail]>
Reviewed-by: Ping Cheng <[e-mail]>
Link: https://github.com/linuxwacom/xf86-input-wacom/issues/71
Fixes: c7f0522a1ad1 ("HID: wacom: Slim down wacom_intuos_pad processing")
Cc: <[e-mail]> # v4.5+
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/hid/wacom_wac.c

···
 		 */
 		buttons = (data[4] << 1) | (data[3] & 0x01);
 	} else if (features->type == CINTIQ_COMPANION_2) {
-		/* d-pad right  -> data[4] & 0x10
-		 * d-pad up     -> data[4] & 0x20
-		 * d-pad left   -> data[4] & 0x40
-		 * d-pad down   -> data[4] & 0x80
-		 * d-pad center -> data[3] & 0x01
+		/* d-pad right  -> data[2] & 0x10
+		 * d-pad up     -> data[2] & 0x20
+		 * d-pad left   -> data[2] & 0x40
+		 * d-pad down   -> data[2] & 0x80
+		 * d-pad center -> data[1] & 0x01
 		 */
 		buttons = ((data[2] >> 4) << 7) |
-		          ((data[1] & 0x04) << 6) |
+		          ((data[1] & 0x04) << 4) |
 		          ((data[2] & 0x0F) << 2) |
 		          (data[1] & 0x03);
 	} else if (features->type >= INTUOS5S && features->type <= INTUOSPL) {