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

Allow comedi pcmcia drivers to use a custom conf_check() when calling
comedi_pcmcia_enable() to enable the pcmcia device. If a conf_check()
is not passed the internal comedi_pcmcia_conf_check() will be used.

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>