FVP_MPS2 family: Disable SERIAL_FC

Looks like `FVP_MPS2 family` has SERIAL_FC feature enabled, but does not provide pins definition for `PinMap_UART_CTS`, `PinMap_UART_RTS`.

This should fix the following failures:
ARMC6::FVP_MPS2_M0
ARMC6::FVP_MPS2_M0P
ARMC6::FVP_MPS2_M3
ARMC6::FVP_MPS2_M4
ARMC6::FVP_MPS2_M7
[Error] serial_api.c@403,12: use of undeclared identifier 'PinMap_UART_CTS'; did you mean 'PinMap_UART_TX'?

Author: mprse

targets/targets.json

@@ -7659,7 +7659,6 @@
             "PORTINOUT",
             "PORTOUT",
             "SERIAL",
-            "SERIAL_FC",
             "TSC",
             "USTICKER"
         ],