Send EAPOL frames at the management rate, not the data rate.

Without this, a far away station with low signal strength would
associate using the management rate (by default the lowest rate)
and then the EAPOL frames would go out at the current AMRR best
guess.  This would result in association failing authentication.

Tested:

* Intel 5100, STA
* Intel 2230, STA
Use IWN_NBANDS rather than a hard-coded limit.

Tested:

* Intel 5100, STA
Fix off-by-one. Sorry!
Replace the hard-coded RX queue value check with IWN_UNSOLICITED_RX_NOTIF.
If A-MPDU transmission fails entirely, then no BA is received from the
NIC and pushed up to the driver.  Unfortunately this means there's
no rate control notification done.  Thus, if the rate control code
makes a decision that hits a crappy rate that can't succeed, the
rate code would never lower the rate and packet loss would continue.

So, fake some rate control notification in this case.