Input: of_keymap - add device tree bindings for simple key matrices

This adds a simple device tree binding for simple key matrix data and
a helper to fill in the platform data.

Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/Kconfig

@@ -25,6 +25,10 @@ config INPUT
 
 if INPUT
 
+config INPUT_OF_MATRIX_KEYMAP
+	depends on USE_OF
+	bool
+
 config INPUT_FF_MEMLESS
 	tristate "Support for memoryless force-feedback devices"
 	help