The flow control is avaliable for this module because it uses QFN32 package. The EZ-Serial FW has already realized the flow control function. You can find it in the EZ-Serial user guide: https://www.cypress.com/file/408286/download
But we don't have a code example for this function. You may refer to the include/Drivers/puart.h for the APIs that enable the flow control and pin assignment.
You may also check this thread to see if it can help: PUART RTS/CTS Hardware Flow Control