ASoC: sgtl5000: rename device tree binding document

It moves and renames sgtl5000 device tree binding document to make
it aligned with other codecs.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/Documentation/devicetree/bindings/sound/soc/codecs/fsl-sgtl5000.txt b/Documentation/devicetree/bindings/sound/sgtl5000.txt
similarity index 100%
rename from Documentation/devicetree/bindings/sound/soc/codecs/fsl-sgtl5000.txt
rename to Documentation/devicetree/bindings/sound/sgtl5000.txt