aes: Clarify IV requirements for OFB mode
Combine the two "must be unique" phrases into one for clarity. An IV
that is universally unique is also unique for each encryption operation.
@@ -324,9 +324,9 @@ int mbedtls_aes_crypt_cfb8( mbedtls_aes_context *ctx,
* you must either save it manually or use the cipher module
* instead.
*
- * \warning For the OFB mode, the initiallisation vector must be unique and
- * must be unique for every encryption operation. Reuse of an
- * initialisation vector will compromise security.
+ * \warning For the OFB mode, the initialisation vector must be unique
+ * every encryption operation. Reuse of an initialisation vector
+ * will compromise security.
*
* \param ctx The AES context to use for encryption or decryption.
* \param length The length of the input data.
