mac80211: do not enable ps if 802.1x controlled port is unblocked

If dynamic_ps is disabled, enabling power save before the 4-way
handshake completes may delay the station from being authorized to
send/receive traffic, i.e. increase roaming times. It also may result in
a failed 4-way handshake depending on the AP's timing requirements and
beacon interval, and the station's listen interval.

To fix this, prevent power save from being enabled while the station
isn't authorized and recalculate power save whenever the station's
authorized state changes.

Signed-off-by: Jason Young <a.young.jason@gmail.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>