xen: fix condition for skipping virtio-mmio defines

GUEST_VIRTIO_MMIO_* was added in Xen 4.17, so only define them
for CONFIG_XEN_CTRL_INTERFACE_VERSIONs up to 4.16.

Reported-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/hw/xen/xen_native.h

@@ -532,7 +532,7 @@ static inline int xendevicemodel_set_irq_level(xendevicemodel_handle *dmod,
 }
 #endif
 
-#if CONFIG_XEN_CTRL_INTERFACE_VERSION <= 41700
+#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 41700
 #define GUEST_VIRTIO_MMIO_BASE   xen_mk_ullong(0x02000000)
 #define GUEST_VIRTIO_MMIO_SIZE   xen_mk_ullong(0x00100000)
 #define GUEST_VIRTIO_MMIO_SPI_FIRST   33