intel_scu_ipc: Protect dev member assignment on ->remove()

Protect the dev member assignment in ->remove() since user may potentially call
unbind from a sysfs even if the driver is built-in. The latter might be racy
with ongoing SCU communication.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>

drivers/platform/x86/intel_scu_ipc.c

@@ -625,7 +625,10 @@ static void ipc_remove(struct pci_dev *pdev)
 {
 	struct intel_scu_ipc_dev *scu = pci_get_drvdata(pdev);
 
+	mutex_lock(&ipclock);
 	scu->dev = NULL;
+	mutex_unlock(&ipclock);
+
 	iounmap(scu->i2c_base);
 	intel_scu_devices_destroy();
 }