rt2x00: Add WCID to crypto struct

When a WCID was already assigned to a STA the key configuration
functions need to use the same WCID for configuring the keys. Hence, add
the WCID to the crypo configuration structure.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>