Fix a typo in comments
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index 6be684e..7d4418e 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -307,7 +307,7 @@
                                               resending messages             */
     unsigned char alt_out_ctr[8];       /*!<  Alternative record epoch/counter
                                               for resending messages         */
-    uint16_t mtu;                       /*!<  Handshake mtu, used to fragment outoing messages */
+    uint16_t mtu;                       /*!<  Handshake mtu, used to fragment outgoing messages */
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
     /*