dbus: Fix an integer overflow when seeking more than ~2000 seconds.

(cherry picked from commit b01b54b0)
Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

modules/control/dbus.c

@@ -222,7 +222,7 @@ DBUS_METHOD( PositionSet )
 
     if( p_input )
     {
-        position.i_time = i_pos * 1000;
+        position.i_time = ((mtime_t)i_pos) * 1000;
         var_Set( p_input, "time", position );
         vlc_object_release( p_input );
     }