Add notifier for mouse mode changes

Right now, DisplayState clients rely on polling the mouse mode to determine
when the device is changed to an absolute device.  Use a notification list to
add an explicit notification.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/console.h b/console.h
index f3c619f..6def115 100644
--- a/console.h
+++ b/console.h
@@ -3,6 +3,7 @@
 
 #include "qemu-char.h"
 #include "qdict.h"
+#include "notify.h"
 
 /* keyboard/mouse support */
 
@@ -56,6 +57,8 @@
 
 /* Does the current mouse generate absolute events */
 int kbd_mouse_is_absolute(void);
+void qemu_add_mouse_mode_change_notifier(Notifier *notify);
+void qemu_remove_mouse_mode_change_notifier(Notifier *notify);
 
 /* Of all the mice, is there one that generates absolute events */
 int kbd_mouse_has_absolute(void);