hw/xenpv: Initialize Xen backend operations

As the Xen backend operations were abstracted out into a function table to
allow for internally emulated Xen support, we missed the xen_init_pv()
code path which also needs to install the operations for the true Xen
libraries. Add the missing call to setup_xen_backend_ops().

Fixes: b6cacfea0b ("hw/xen: Add evtchn operations to allow redirection to internal emulation")
Reported-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Tested-by: Anthony PERARD <anthony.perard@citrix.com>
Message-Id: <5dfb65342d4502c1ce2f890c97cff20bf25b3860.camel@infradead.org>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

hw/xenpv/xen_machine_pv.c

@@ -35,6 +35,8 @@ static void xen_init_pv(MachineState *machine)
     DriveInfo *dinfo;
     int i;
 
+    setup_xen_backend_ops();
+
     /* Initialize backend core & drivers */
     xen_be_init();