dt-bindings: Add devicetree bindings

Add snapshot of device tree bindings from keystone common kernel, branch
"android-mainline-keystone-qcom-release" at c4c12103f9c0 ("Snap for 9228065
from e32903b9a63bb558df8b803b076619c53c16baad to
android-mainline-keystone-qcom-release").

Change-Id: I7682079615cbd9f29340a5c1f2a1d84ec441a1f1
Signed-off-by: Melody Olvera <quic_molvera@quicinc.com>

bindings/memory-controllers/ddr/jedec,lpddr4.yaml

@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memory-controllers/ddr/jedec,lpddr4.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: LPDDR4 SDRAM compliant to JEDEC JESD209-4
+
+maintainers:
+  - Krzysztof Kozlowski <krzk@kernel.org>
+
+allOf:
+  - $ref: jedec,lpddr-props.yaml#
+
+properties:
+  compatible:
+    items:
+      - pattern: "^lpddr4-[0-9a-f]{2},[0-9a-f]{4}$"
+      - const: jedec,lpddr4
+
+required:
+  - compatible
+  - density
+  - io-width
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    lpddr {
+        compatible = "lpddr4-ff,0100", "jedec,lpddr4";
+        density = <8192>;
+        io-width = <16>;
+        revision-id = <1 0>;
+    };