staging: comedi: quatech_daqp_cs: fix build error

The kbuild test robot reported a build error in this driver caused by:

commit: a3ac95195b020a0a8fa2a9b0649145324ba64c83
staging: comedi: comedi_pcmcia: allow drivers to use a custom conf_check()

This commit changed the comedi_pcmcia_enable() function so that it now
takes two arguments. The new argument is an optional (*conf_check)
function that is passed to pcmcia_loop_config().

This driver uses the default (*conf_check) in comedi_pcmcia.c so just
pass a NULL as the second arg.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>