staging: wilc1000: remove wilc_debugfs.c file as its not used

Deleted wilc_debugfs.c file as it's not used.

Earlier discussion link:
[1]. https://www.spinics.net/lists/linux-wireless/msg176076.html



Suggested-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>