TSCH: use default MAX_BE
#ifdef TSCH_CONF_MAC_MAX_BE
#define TSCH_MAC_MAX_BE TSCH_CONF_MAC_MAX_BE
#else
-#define TSCH_MAC_MAX_BE 7
+#define TSCH_MAC_MAX_BE 5
#endif
/* Max number of re-transmissions */
#ifdef TSCH_CONF_MAC_MAX_FRAME_RETRIES
