Unified multiple definitions of container_of() macro.

Removed duplicate definitions of the container_of() macro and
refactored sources to use the single implementation.

Signed-off-by: Jon A. Cruz <jonc@osg.samsung.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>

ivi-shell/hmi-controller.c

@@ -60,6 +60,7 @@
 
 #include "ivi-layout-export.h"
 #include "ivi-hmi-controller-server-protocol.h"
+#include "shared/helpers.h"
 
 /*****************************************************************************
  *  structure, globals

ivi-shell/input-panel-ivi.c

@@ -34,6 +34,7 @@
 #include "ivi-shell.h"
 #include "input-method-server-protocol.h"
 #include "ivi-layout-private.h"
+#include "shared/helpers.h"
 
 struct input_panel_surface {
 	struct wl_resource *resource;

ivi-shell/ivi-layout.c

@@ -63,6 +63,7 @@
 #include "ivi-layout-export.h"
 #include "ivi-layout-private.h"
 
+#include "shared/helpers.h"
 #include "shared/os-compatibility.h"
 
 struct link_layer {