ivi-shell: rename ivi_controller_interface

The name of ivi_controller_interface is changed to ivi_layout_interface
with this patch.

This name is better suited to the interface, because it is implemented
in ivi-layout.c and its methods are linked to ivi_layout* functions.

Furthermore, the controller modules (e.g. hmi-controller) are the users
of this interface and they have their own interfaces,
which are called *_controller_interface,
e.g.: ivi_hmi_controller_interface.

This causes confusion about the software architecture.

Signed-off-by: Emre Ucan <eucan@de.adit-jv.com>
Tested-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>
Reviewed-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>
diff --git a/ivi-shell/ivi-layout-export.h b/ivi-shell/ivi-layout-export.h
index 8a92009..54af286 100644
--- a/ivi-shell/ivi-layout-export.h
+++ b/ivi-shell/ivi-layout-export.h
@@ -173,7 +173,7 @@
 			int32_t content,
 			void *userdata);
 
-struct ivi_controller_interface {
+struct ivi_layout_interface {
 
 	/**
 	 * \brief Commit all changes and execute all enqueued commands since