staging: comedi: ni_daq_700: use a local var to fix a > 80 char line issue

The 'data[1] = ...' line is currently kept < 80 chars by breaking a pointer
access after the '->'. This makes the code a bit confusing to follow. Use
a local variable to shorten the line and make it clearer.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Frank Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>