memif: do not mask head and tail pointers

Change-Id: Ie849ab713ff086187c18a91ab32e58207fe94033
Signed-off-by: Damjan Marion <damarion@cisco.com>
Signed-off-by: Jakub Grajciar <Jakub.Grajciar@pantheon.tech>
diff --git a/extras/libmemif/src/libmemif.h b/extras/libmemif/src/libmemif.h
index da48edd..3fc0648 100644
--- a/extras/libmemif/src/libmemif.h
+++ b/extras/libmemif/src/libmemif.h
@@ -73,6 +73,7 @@
   MEMIF_ERR_DISCONNECTED,	/*!< peer interface disconnected */
   MEMIF_ERR_UNKNOWN_MSG,	/*!< unknown message type */
   MEMIF_ERR_POLL_CANCEL,	/*!< memif_poll_event() was cancelled */
+  MEMIF_ERR_MAX_RING,		/*!< too large ring size */
 } memif_err_t;
 
 /**