wl1271: prevent power save entry while not associated

The mac80211 sometimes requests power save entry while not associated - this
will cause problems, so prevent it if not associated. Go to powersave once
association is complete.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>