Don't clobber the firmware's internal state machine by setting
ENABLE_RSN more than once during the 4-way handshake.  Check what
the ENABLE_RSN status is and only set if it should be changed.
Signed-off-by: NDan Williams <dcbw@redhat.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>