Updated port.c to freeRTOS 7.4.0 and added freeRTOSConfigxxx.h missing files

Updated port.c to freeRTOS 7.4.0, and repaired added freeRTOSConfig****.h missing files

I make an update to port.c file to reflect your changes
I put in arduino.DuinOS the files named freeRTOSConfig*****. files. 'cause they where missing