It programs the application FPGA using a dedicated char device.
On open() it resets the FPGA
On write() it copies the bitstream on the FPGA
On close() it copies the last word on the bitstream and it enables
the application FPGA
In order to be able to program the application FPGA the user must unlock
the flashing procedure by writing 'unlock' in the `lock` sysfs attribute
 This hack is necessary does to an FPGA programmer limitation