tests: Permit encryption of Deauthentication frame

tests: Permit encryption of Deauthentication frame

The test does not intentionally send an unencrypted frame. This seems to
simply be done because the parameter value is not obvious. Change it to
permit encryption so that the frame can be sent directly rather than
going through the monitor interface.

This really doesn't make a difference overall, but it is closer to what
was intended here.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>