xen_backend: make the xen_feature_grant_copy flag private

There is no longer any use of this flag outside of the xen_backend code.
Signed-off-by: NPaul Durrant <paul.durrant@citrix.com>
Acked-by: NAnthony Perard <anthony.perard@citrix.com>
Signed-off-by: NStefano Stabellini <sstabellini@kernel.org>

hw/xen/xen_backend.c

@@ -44,9 +44,9 @@ BusState *xen_sysbus;
 /* public */
 struct xs_handle *xenstore = NULL;
 const char *xen_protocol;
-bool xen_feature_grant_copy;
 
 /* private */
+static bool xen_feature_grant_copy;
 static int debug;
 
 int xenstore_write_be_str(struct XenDevice *xendev, const char *node, const char *val)

include/hw/xen/xen_backend.h

@@ -16,7 +16,6 @@
 /* variables */
 extern struct xs_handle *xenstore;
 extern const char *xen_protocol;
-extern bool xen_feature_grant_copy;
 extern DeviceState *xen_sysdev;
 extern BusState *xen_sysbus;