Staging: comedi: Fixed coding style issues.

comedi_fops.c : A forward decleration was declared as extern although it
                is a function private to this file. Changed the
                decleration to static.
Signed-off-by: NMark Pearson <markpearson_de@yahoo.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/comedi/comedi_fops.c

@@ -101,7 +101,7 @@ static int do_insn_ioctl(struct comedi_device *dev,
 static int do_poll_ioctl(struct comedi_device *dev, unsigned int subd,
 			 void *file);
 
-extern void do_become_nonbusy(struct comedi_device *dev,
+static void do_become_nonbusy(struct comedi_device *dev,
 			      struct comedi_subdevice *s);
 static int do_cancel(struct comedi_device *dev, struct comedi_subdevice *s);