The SPEC is made of its PCI bridge (GN4124) and a set of FPGA
devices that enables some carrier feature. The first one is handled
by the Linux pci_dev, the second set of devices have a commond parent
that I am moving into the spec-core-fpga.c file so that all FPGA related
code is in one place
Signed-off-by: Federico Vaga <federico.vaga@cern.ch>