Merge branch 'bugfix/modbus_rtu_skips_first_packet_t35meas_is_disabled' into 'master'

Bugfix/modbus rtu skips first packet t35meas is disabled

Closes IDFGH-12105

See merge request idf/esp-modbus!58

freemodbus/modbus/rtu/mbrtu.c

@@ -137,8 +137,11 @@ eMBRTUStart( void )
      */
     eRcvState = STATE_RX_INIT;
     vMBPortSerialEnable( TRUE, FALSE );
-    vMBPortTimersEnable(  );
-
+#if CONFIG_FMB_TIMER_PORT_ENABLED
+    vMBPortTimersEnable( );
+#else
+    pxMBPortCBTimerExpired();
+#endif
     EXIT_CRITICAL_SECTION(  );
 }