pcmcia: cs: kill thread_wait

There is not reason to have a waitqueue if it's always the same
thread that is waiting for it.  Just use wake_up_process instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Small modification: Also remove unused variable.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>