dt-bindings: mtd: move partition binding to its own file

Single partition binding is quite common and may be:
1. Used by multiple parsers
2. Extended for more specific cases

Move it to separated file to avoid code duplication.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>

Documentation/devicetree/bindings/mtd/partitions/fixed-partitions.yaml

@@ -27,38 +27,7 @@ properties:
 
 patternProperties:
   "@[0-9a-f]+$":
-    description: node describing a single flash partition
-    type: object
-
-    properties:
-      reg:
-        description: partition's offset and size within the flash
-        maxItems: 1
-
-      label:
-        description: The label / name for this partition. If omitted, the label
-          is taken from the node name (excluding the unit address).
-
-      read-only:
-        description: This parameter, if present, is a hint that this partition
-          should only be mounted read-only. This is usually used for flash
-          partitions containing early-boot firmware images or data which should
-          not be clobbered.
-        type: boolean
-
-      lock:
-        description: Do not unlock the partition at initialization time (not
-          supported on all devices)
-        type: boolean
-
-      slc-mode:
-        description: This parameter, if present, allows one to emulate SLC mode
-          on a partition attached to an MLC NAND thus making this partition
-          immune to paired-pages corruptions
-        type: boolean
-
-    required:
-      - reg
+    $ref: "partition.yaml#"
 
 required:
   - "#address-cells"

Documentation/devicetree/bindings/mtd/partitions/partition.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mtd/partitions/partition.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Partition
+
+description: |
+  This binding describes a single flash partition. Each partition must have its
+  relative offset and size specified. Depending on partition function extra
+  properties can be used.
+
+maintainers:
+  - Rafał Miłecki <rafal@milecki.pl>
+
+properties:
+  reg:
+    description: partition's offset and size within the flash
+    maxItems: 1
+
+  label:
+    description: The label / name for this partition. If omitted, the label
+      is taken from the node name (excluding the unit address).
+
+  read-only:
+    description: This parameter, if present, is a hint that this partition
+      should only be mounted read-only. This is usually used for flash
+      partitions containing early-boot firmware images or data which should
+      not be clobbered.
+    type: boolean
+
+  lock:
+    description: Do not unlock the partition at initialization time (not
+      supported on all devices)
+    type: boolean
+
+  slc-mode:
+    description: This parameter, if present, allows one to emulate SLC mode
+      on a partition attached to an MLC NAND thus making this partition
+      immune to paired-pages corruptions
+    type: boolean
+
+required:
+  - reg
+
+additionalProperties: true