staging: comedi: comedi_fops: rename struct comedi_device_file_info

For aesthetic reasons, rename this struct to comedi_file_info. It's
a bit shorter and allows fixing some of the ugly line breaks used
to keep the lines < 80 chars.

Also, consistently use the local variable name 'info' instead of the
longer 'dev_file_info' to also fix some ugly line breaks.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>