vfio: make vfio_address_spaces static

It is not used outside hw/vfio/common.c, so it does not need to
be extern.

Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/vfio/common.c

@@ -39,7 +39,7 @@
 
 struct vfio_group_head vfio_group_list =
     QLIST_HEAD_INITIALIZER(vfio_group_list);
-struct vfio_as_head vfio_address_spaces =
+static QLIST_HEAD(, VFIOAddressSpace) vfio_address_spaces =
     QLIST_HEAD_INITIALIZER(vfio_address_spaces);
 
 #ifdef CONFIG_KVM

include/hw/vfio/vfio-common.h

@@ -181,7 +181,6 @@ int vfio_get_device(VFIOGroup *group, const char *name,
 
 extern const MemoryRegionOps vfio_region_ops;
 extern QLIST_HEAD(vfio_group_head, VFIOGroup) vfio_group_list;
-extern QLIST_HEAD(vfio_as_head, VFIOAddressSpace) vfio_address_spaces;
 
 #ifdef CONFIG_LINUX
 int vfio_get_region_info(VFIODevice *vbasedev, int index,