Work around compressed EC public key in some cases
diff --git a/include/polarssl/ecp.h b/include/polarssl/ecp.h
index b35b0d1..61d6a1d 100644
--- a/include/polarssl/ecp.h
+++ b/include/polarssl/ecp.h
@@ -376,8 +376,10 @@
* \param ilen Actual length of input
*
* \return 0 if successful,
- * POLARSSL_ERR_ECP_BAD_INPUT_DATA if input is invalid
- * POLARSSL_ERR_MPI_MALLOC_FAILED if memory allocation failed
+ * POLARSSL_ERR_ECP_BAD_INPUT_DATA if input is invalid,
+ * POLARSSL_ERR_MPI_MALLOC_FAILED if memory allocation failed,
+ * POLARSSL_ERR_ECP_FEATURE_UNAVAILABLE if the point format
+ * is not implemented.
*
* \note This function does NOT check that the point actually
* belongs to the given group, see ecp_check_pubkey() for