memory: add owner argument to initialization functions

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/hw/timer/omap_gptimer.c b/hw/timer/omap_gptimer.c
index 9b0e9dd..ac389d8 100644
--- a/hw/timer/omap_gptimer.c
+++ b/hw/timer/omap_gptimer.c
@@ -480,7 +480,7 @@
     omap_gp_timer_reset(s);
     omap_gp_timer_clk_setup(s);
 
-    memory_region_init_io(&s->iomem, &omap_gp_timer_ops, s, "omap.gptimer",
+    memory_region_init_io(&s->iomem, NULL, &omap_gp_timer_ops, s, "omap.gptimer",
                           omap_l4_region_size(ta, 0));
     omap_l4_attach(ta, 0, &s->iomem);