Fix potential bug in CBOR encoding.

It happen if a keepalive packet is sent in the middle of an encoding.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

src/fido/cbor_large_blobs.c

@@ -79,7 +79,7 @@ int cbor_large_blobs(const uint8_t *data, size_t len) {
         CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);
     }
 
-    cbor_encoder_init(&encoder, ctap_resp->init.data + 1, CTAP_MAX_PACKET_SIZE, 0);
+    cbor_encoder_init(&encoder, res_APDU + 1, CTAP_MAX_PACKET_SIZE, 0);
     if (get > 0) {
         if (length != 0) {
             CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);