staging: vt6656: [bug] Fix missing spin lock in iwctl_siwpower.

Fixes occasional dead lock on power up / down.

spin_lock_irq is used because of unlocking with spin_unlock_irq
elsewhere in the driver.

Only relevant to kernels 3.8 and later when command was
transferred to the iw_handler.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Cc: stable@vger.kernel.org # 3.8+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6656/iwctl.c

@@ -1345,9 +1345,12 @@ int iwctl_siwpower(struct net_device *dev, struct iw_request_info *info,
 		return rc;
 	}
 
+	spin_lock_irq(&pDevice->lock);
+
 	if (wrq->disabled) {
 		pDevice->ePSMode = WMAC_POWER_CAM;
 		PSvDisablePowerSaving(pDevice);
+		spin_unlock_irq(&pDevice->lock);
 		return rc;
 	}
 	if ((wrq->flags & IW_POWER_TYPE) == IW_POWER_TIMEOUT) {
@@ -1358,6 +1361,9 @@ int iwctl_siwpower(struct net_device *dev, struct iw_request_info *info,
 		pDevice->ePSMode = WMAC_POWER_FAST;
 		PSvEnablePowerSaving((void *)pDevice, pMgmt->wListenInterval);
 	}
+
+	spin_unlock_irq(&pDevice->lock);
+
 	switch (wrq->flags & IW_POWER_MODE) {
 	case IW_POWER_UNICAST_R:
 		DBG_PRT(MSG_LEVEL_DEBUG, KERN_INFO " SIOCSIWPOWER: IW_POWER_UNICAST_R \n");