Remove SERIAL_FC from the ARM_IOTSS_BEID
Remove SERIAL_FC from the ARM_IOTSS_BEID

The ARM_IOTSS_BEID does not support flow control in its serial driver so it
should not have SERIAL_FC in device_has.

andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,kjbracey-arm/mbed,mbedmicro/mbed,andcor02/mbed-os,kjbracey-arm/mbed,mbedmicro/mbed,mbedmicro/mbed,andcor02/mbed-os,andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,andcor02/mbed-os