fix: avoid spurious WARN in rwnx_close during USB teardown

Unplugging the adapter while the interface is connecting or disconnecting
prints a spurious kernel warning:

  rwnx_close connecting or disconnecting, not finish
  WARNING: CPU: ... rwnx_close+0x96/0x3f0 [aic8800_fdrv]

rwnx_close() waits up to 4 seconds for drv_conn_state to leave
CONNECTING/DISCONNECTING, but that state only changes when the firmware
answers the pending request. During USB teardown the bus is already down
by the time rwnx_close() runs, and rwnx_send_msg() drops the message and
returns 0, so the confirmation never arrives. The wait therefore always
runs its full timeout and fires WARN_ON(1) for a condition that cannot be
satisfied.

Skip both waits when the bus is down, using the same condition already
used a few lines below in the vif_started path. This removes the wait
itself, not just the warning: previously teardown blocked for up to 4 (and
2) seconds waiting on a dead bus.

Reproduced on 6.12.107+deb13 with an AIC8800D80: unplug while connected
fires the warning on main and produces none with this change, while the
replug path still re-enumerates and restores Wi-Fi and Bluetooth. Builds
on 5.15.0-191, 6.1.0-53, 6.8.0-139, 6.11.0-8 and 6.12.107+deb13 with no
new warnings.

drivers/aic8800/aic8800_fdrv/rwnx_main.c

@@ -1518,6 +1518,17 @@ static int rwnx_close(struct net_device *dev)
 
     RWNX_DBG(RWNX_FN_ENTRY_STR);
 
+    /*
+     * A CONNECTING/DISCONNECTING state is only left when the firmware answers
+     * the pending request. If the bus is already down the answer can never
+     * arrive: rwnx_send_msg() silently drops the message and returns 0
+     * (rwnx_msg_tx.c), so the wait below would always run its full timeout and
+     * fire the spurious WARN_ON() during USB teardown. Skip the wait when the
+     * bus is down, using the same condition the vif_started path uses below.
+     */
+    if (bus_if &&
+        (usbdev == NULL || (usbdev->bus_if->state != BUS_DOWN_ST &&
+                            usbdev->state != USB_DOWN_ST))) {
         test_counter = waiting_counter;
         while(atomic_read(&rwnx_vif->drv_conn_state) == (int)RWNX_DRV_STATUS_DISCONNECTING||
             atomic_read(&rwnx_vif->drv_conn_state) == (int)RWNX_DRV_STATUS_CONNECTING){
@@ -1530,6 +1541,7 @@ static int rwnx_close(struct net_device *dev)
                 break;
             }
         }
+    }
 
 #if defined(AICWF_USB_SUPPORT) || defined(AICWF_SDIO_SUPPORT)
     if (rwnx_hw->scanning){
@@ -1587,6 +1599,10 @@ static int rwnx_close(struct net_device *dev)
 			test_counter = waiting_counter;
 			if(atomic_read(&rwnx_vif->drv_conn_state) == (int)RWNX_DRV_STATUS_CONNECTED){
 				rwnx_set_conn_state(rwnx_vif, &rwnx_vif->drv_conn_state, RWNX_DRV_STATUS_DISCONNECTING);
+				/* Same reasoning as above: with the bus down the disconnect
+				 * confirmation cannot arrive, so do not wait for it. */
+				if (usbdev->bus_if->state != BUS_DOWN_ST &&
+				    usbdev->state != USB_DOWN_ST) {
 					rwnx_send_sm_disconnect_req(rwnx_hw, rwnx_vif, 3);
 					while (atomic_read(&rwnx_vif->drv_conn_state) == (int)RWNX_DRV_STATUS_DISCONNECTING) {
 						AICWFDBG(LOGDEBUG, "%s wifi is disconnecting, waiting 100ms for state to stable\r\n", __func__);
@@ -1597,6 +1613,7 @@ static int rwnx_close(struct net_device *dev)
 					}
 				}
 			}
+		}
 #ifdef CONFIG_USE_P2P0
         if(!rwnx_vif->is_p2p_vif || ( rwnx_vif->is_p2p_vif && rwnx_hw->is_p2p_alive)){
 			if (rwnx_vif->is_p2p_vif)