rtlwifi: pci: Fix oops on driver unload

On Fedora systems, unloading rtl8192ce causes an oops. This patch fixes the
problem reported at https://bugzilla.redhat.com/show_bug.cgi?id=852761.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtlwifi/pci.c

@@ -740,6 +740,8 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
 	};
 	int index = rtlpci->rx_ring[rx_queue_idx].idx;
 
+	if (rtlpci->driver_is_goingto_unload)
+		return;
 	/*RX NORMAL PKT */
 	while (count--) {
 		/*rx descriptor */
@@ -1636,6 +1638,7 @@ static void rtl_pci_stop(struct ieee80211_hw *hw)
 	 */
 	set_hal_stop(rtlhal);
 
+	rtlpci->driver_is_goingto_unload = true;
 	rtlpriv->cfg->ops->disable_interrupt(hw);
 	cancel_work_sync(&rtlpriv->works.lps_change_work);
 
@@ -1653,7 +1656,6 @@ static void rtl_pci_stop(struct ieee80211_hw *hw)
 	ppsc->rfchange_inprogress = true;
 	spin_unlock_irqrestore(&rtlpriv->locks.rf_ps_lock, flags);
 
-	rtlpci->driver_is_goingto_unload = true;
 	rtlpriv->cfg->ops->hw_disable(hw);
 	/* some things are not needed if firmware not available */
 	if (!rtlpriv->max_fw_size)