Having an SPI interface does not mean that it is active after power-up and able to fetch instructions (and to instruct a core to execute them afterwards).
Mikrocontrollers contain built-in flash or ROM storage, which either contains the firmware or all the code needed to load and execute the firmware.
If the eLink can be run sufficiently slow - I think it can - then you won't need an FPGA to bootstrap the Epiphany. But you'd still need a controller.