dt-bindings: Relocate DDR bindings

Move DDR bindings to memory-controllers directory to make them more
discoverable.
Suggested-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211006224659.21434-2-digetx@gmail.com
[krzysztof: Correct path in lpddr3.txt and samsung,exynos5422-dmc.yaml]
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

Documentation/devicetree/bindings/ddr/lpddr3.txt → Documentation/devicetree/bindings/memory-controllers/ddr/lpddr3.txt

@@ -43,8 +43,9 @@ These values shall be obtained from the device data-sheet.
 Child nodes:
 - The lpddr3 node may have one or more child nodes of type "lpddr3-timings".
   "lpddr3-timings" provides AC timing parameters of the device for
-  a given speed-bin. Please see Documentation/devicetree/
-  bindings/ddr/lpddr3-timings.txt for more information on "lpddr3-timings"
+  a given speed-bin. Please see
+  Documentation/devicetree/bindings/memory-controllers/ddr/lpddr3-timings.txt
+  for more information on "lpddr3-timings"
 
 Example:
 

Documentation/devicetree/bindings/memory-controllers/samsung,exynos5422-dmc.yaml

@@ -51,7 +51,8 @@ properties:
     $ref: '/schemas/types.yaml#/definitions/phandle'
     description: |
       phandle of the connected DRAM memory device. For more information please
-      refer to documentation file: Documentation/devicetree/bindings/ddr/lpddr3.txt
+      refer to documentation file:
+      Documentation/devicetree/bindings/memory-controllers/ddr/lpddr3.txt
 
   operating-points-v2: true