b43: Avoid possible double calls to b43_one_core_detach()

In b43_request_firmware(), when ieee80211_register_hw() fails,
b43_one_core_detach() is called. In b43_bcma_remove() and
b43_ssb_remove(), b43_one_core_detach() is called again. In this case,
null-pointer dereferences and double-free problems can occur when
the driver is removed.

To fix this bug, the call to b43_one_core_detach() in
b43_request_firmware() is deleted.

This bug is found by a runtime fuzzing tool named FIZZER written by us.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/broadcom/b43/main.c

@@ -2590,18 +2590,13 @@ static void b43_request_firmware(struct work_struct *work)
 
 	err = ieee80211_register_hw(wl->hw);
 	if (err)
-		goto err_one_core_detach;
+		goto out;
 	wl->hw_registered = true;
 	b43_leds_register(wl->current_dev);
 
 	/* Register HW RNG driver */
 	b43_rng_init(wl);
 
-	goto out;
-
-err_one_core_detach:
-	b43_one_core_detach(dev->dev);
-
 out:
 	kfree(ctx);
 }