PCI: pciehp: Always protect pciehp_disable_slot() with hotplug mutex

When called from pciehp_sysfs_disable_slot(), the call to
pciehp_disable_slot() was not protected by the hotplug mutex.

Hold slot->hotplug_lock while calling pciehp_disable_slot().
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rajat Jain <rajatxjain@gmail.com>

drivers/pci/hotplug/pciehp_ctrl.c

@@ -511,7 +511,9 @@ int pciehp_sysfs_disable_slot(struct slot *p_slot)
 	case STATIC_STATE:
 		p_slot->state = POWEROFF_STATE;
 		mutex_unlock(&p_slot->lock);
+		mutex_lock(&p_slot->hotplug_lock);
 		retval = pciehp_disable_slot(p_slot);
+		mutex_unlock(&p_slot->hotplug_lock);
 		mutex_lock(&p_slot->lock);
 		p_slot->state = STATIC_STATE;
 		break;