rt2800usb:fix hang during firmware load

rt2800usb:fix hang during firmware load

The device 057c:8501 (AVM Fritz! WLAN v2 rev. B) boots into a state that does
not actually require loading a firmware file. The vendors driver finds out
about this by checking a firmware state register, so this patch adds this here.

Finally, with this patch applied, my wifi dongle actually becomes
useful (scan + connect to wpa network works).

Signed-off-by: Michael Braun <[email protected]>
Acked-by: Stanislaw Gruszka <[email protected]>
Signed-off-by: John W. Linville <[email protected]>