For FPGA re-programming, debugfs was used. For this purpose, the
corresponding function was making use of 'device_schedule_callback()'
which was removed in linux-v3.15 at commit:
	33ac1257ff0dee2e9c7f009b1c1914b7990217b2 ("sysfs, driver-core:
	remove unused {sysfs|device}_schedule_callback_owner()")

The similar and better functionality is provided by an sysfs-API
'device_remove_file_self()'. Thus, convert this procedure from debugfs to
sysfs.
Signed-off-by: Vaibhav Gupta <vaibhav.gupta@cern.ch>