pcmcia: validate CIS, not CIS cache.

In pccard_validate_cis(), validate the card CIS, not the CIS cache.
Also, destroy the CIS cache if pccard_validate_cis fails.

Furthermore, do not remove the fake CIS in destroy_cis_cache() but
do so explicitely in the code paths where it makes sense.

Tested-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>