staging: vt6656: Fix return for unsupported cipher modes.

mac80211 expect to see -EOPNOTSUPP on unsupported ciphers so
these can be done on stack.

correct all the returns to do this.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/b65a3b23-735f-f679-0f16-a54c3266b5ae@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>