Add macro for large blob size.

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

src/fido/fido.h

@@ -81,6 +81,7 @@ extern void set_opts(uint8_t);
 #define MAX_CREDBLOB_LENGTH       128
 #define MAX_MSG_SIZE              1024
 #define MAX_FRAGMENT_LENGTH       (MAX_MSG_SIZE - 64)
+#define MAX_LARGE_BLOB_SIZE       2048
 
 typedef struct known_app {
     const uint8_t *rp_id_hash;