pcmcia: use state machine for extended requery

The requery callback now also handles the addition of a second pseudo
multifunction device. Avoids messing with dev_{g,s}et_drvdata(), and
fixes any workqueue <-> skt_mutex deadlock.

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