memory: omap-gpmc: Move device tree binding to correct location

omap-gpmc.c is a memory controller so move the binding to the
right place.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Tony Lindgren <tony@atomide.com>

diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt
similarity index 100%
rename from Documentation/devicetree/bindings/bus/ti-gpmc.txt
rename to Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt