Add OFB block mode to AES-128/192/256

Adds a new configuration of MBEDTLS_CIPHER_MODE_OFB and OFB mode to AES.
diff --git a/library/version_features.c b/library/version_features.c
index a452caf..218a892 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -246,6 +246,9 @@
 #if defined(MBEDTLS_CIPHER_MODE_CBC)
     "MBEDTLS_CIPHER_MODE_CBC",
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
+#if defined(MBEDTLS_CIPHER_MODE_OFB)
+    "MBEDTLS_CIPHER_MODE_OFB",
+#endif /* MBEDTLS_CIPHER_MODE_OFB */
 #if defined(MBEDTLS_CIPHER_MODE_CFB)
     "MBEDTLS_CIPHER_MODE_CFB",
 #endif /* MBEDTLS_CIPHER_MODE_CFB */