staging: kpc2000: removed superfluous NULL checks from device attribute call-backs.

All the attribute show call-backs check whether pcard is NULL.  However,
pci_set_drvdata(pdev, pcard) is called before the sysfs files are
created during probe, and pci_set_drvdata(pdev, NULL) is not called
until after they are destroyed during remove; therefore, pcard will not
be NULL, and we can drop the checks.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>