at86rf230: mask irq's before deregister device

While transmit over a at86rf231 device and unloading the module I got:

[   29.643073] WARNING: CPU: 0 PID: 3 at kernel/workqueue.c:1335 __queue_work+0xb4/0x224()
[   29.651457] Modules linked in: at86rf230(-) autofs4
[   29.656612] CPU: 0 PID: 3 Comm: ksoftirqd/0 Tainted: G        W    3.14.0-rc6-01602-g902659e-dirty #294
[   29.666490] [<c00124f0>] (unwind_backtrace) from [<c0010ad0>] (show_stack+0x10/0x14)
[   29.674628] [<c0010ad0>] (show_stack) from [<c0032c80>] (warn_slowpath_common+0x60/0x80)
[   29.683116] [<c0032c80>] (warn_slowpath_common) from [<c0032d30>] (warn_slowpath_null+0x18/0x20)
[   29.692329] [<c0032d30>] (warn_slowpath_null) from [<c0045b08>] (__queue_work+0xb4/0x224)
[   29.700906] [<c0045b08>] (__queue_work) from [<c0045cc8>] (queue_work_on+0x50/0x78)
[   29.708944] [<c0045cc8>] (queue_work_on) from [<c05669cc>] (mac802154_tx+0x1e4/0x240)
[   29.717164] [<c05669cc>] (mac802154_tx) from [<c0471814>] (dev_hard_start_xmit+0x2f0/0x43c)
[   29.725926] [<c0471814>] (dev_hard_start_xmit) from [<c04878d0>] (sch_direct_xmit+0x64/0x2a0)
[   29.734867] [<c04878d0>] (sch_direct_xmit) from [<c0487c38>] (__qdisc_run+0x12c/0x18c)
[   29.743169] [<c0487c38>] (__qdisc_run) from [<c046e1b0>] (net_tx_action+0xe0/0x178)
[   29.751205] [<c046e1b0>] (net_tx_action) from [<c0036690>] (__do_softirq+0x100/0x264)
[   29.759420] [<c0036690>] (__do_softirq) from [<c0036818>] (run_ksoftirqd+0x24/0x4c)
[   29.767453] [<c0036818>] (run_ksoftirqd) from [<c005232c>] (smpboot_thread_fn+0x128/0x13c)
[   29.776121] [<c005232c>] (smpboot_thread_fn) from [<c004c3fc>] (kthread+0xd0/0xe4)
[   29.784061] [<c004c3fc>] (kthread) from [<c000da88>] (ret_from_fork+0x14/0x2c)
[   29.791628] ---[ end trace 3406ff24bd973834 ]---

The problem is there are still interrupts after deregister ieee802154
device. This patch mask all interrupts in the at86rf2xx chips before
deregister the device.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ieee802154/at86rf230.c

@@ -997,6 +997,8 @@ static int at86rf230_remove(struct spi_device *spi)
 {
 	struct at86rf230_local *lp = spi_get_drvdata(spi);
 
+	/* mask all at86rf230 irq's */
+	at86rf230_write_subreg(lp, SR_IRQ_MASK, 0);
 	ieee802154_unregister_device(lp->dev);
 
 	free_irq(spi->irq, lp);