rt2x00: Disable auto wakeup before waking up device.

In all drivers ensure that auto wakeup is disabled before waking up the device.
This is needed to prevent connection stability issues and problems in waking up
the device.

Based upon a patch from Ondrej Zary <linux@rainbow-software.org>

Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Cc: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>