[PATCH] pcmcia: clean up cs ds callback

struct pcmcia_callback isn't needed for each socket, one is enough for all
sockets.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>