Otherwise this may give the false impression the some explicit locking
is done in this code.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- a/xen/drivers/passthrough/vtd/x86/ats.c
+++ b/xen/drivers/passthrough/vtd/x86/ats.c
@@ -40,7 +40,6 @@ struct pci_ats_dev {
     u8 bus;
     u8 devfn;
     u16 ats_queue_depth;    /* ATS device invalidation queue depth */
-    spinlock_t lock;
 };
 static LIST_HEAD(ats_devices);