ARM: shmobile: lager: Add DT reference

This is sufficient to allow boot of the Lager board with
a console without boards-lager.c compiled into the kernel.
This is an example of a minimal but still useful initialisation
of the board using DT as much as possible.

As such it is the same as the boot of Lager that can be achieved
without a board file. The intention of adding this file
is to facilitate further work to allow board specific devices to be
initialised via DT.

Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index ad28f91..05ea103 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -161,6 +161,17 @@
 	depends on ARCH_R8A7790
 	select USE_OF
 
+config MACH_LAGER_REFERENCE
+	bool "Lager board - Reference Device Tree Implementation"
+	depends on ARCH_R8A7790
+	select USE_OF
+	---help---
+	   Use reference implementation of Lager board support
+	   which makes use of device tree at the expense
+	   of not supporting a number of devices.
+
+	   This is intended to aid developers
+
 config MACH_KZM9D
 	bool "KZM9D board"
 	depends on ARCH_EMEV2