drivers/pcmcia/electra_cf.c: add missing iounmap and kfree

cf and cf->mem_base have been allocated at the point of this failure, so
they should be freed before leaving the function.

[linux@dominikbrodowski.net: limit call to device_init_wakeup() to the
same error paths as before]
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>