rt2800usb: check Autorun mode on FW load only once

Seems H/W report correctly firmware Autorun value only at initialization
stage. When we close interface and open it again, Autorun value is 0 and
we try to load firmware what kills the device. To fix clear
REQUIRE_FIRMWARE firmware flag, to do not load firmware again, once we
discover Autorun mode.
Reported-and-tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/rt2x00/rt2800usb.c

@@ -293,6 +293,7 @@ static int rt2800usb_write_firmware(struct rt2x00_dev *rt2x00dev,
 	if (retval) {
 		rt2x00_info(rt2x00dev,
 			    "Firmware loading not required - NIC in AutoRun mode\n");
+		__clear_bit(REQUIRE_FIRMWARE, &rt2x00dev->cap_flags);
 	} else {
 		rt2x00usb_register_multiwrite(rt2x00dev, FIRMWARE_IMAGE_BASE,
 					      data + offset, length);