pcmcia: remove CS_ error codes alltogether

Remoe the CS_ error codes. Drivers are expected to use default
error definitions (errno.h etc.).

Only one CS_ error code -- CS_IN_USE -- is used internally by the
(deprecated) pcmcia-cs userspace package. Therefore, keep this one
around so that it still compiles.

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