dt-bindings: mtd: ubi-volume: allow UBI volumes to provide NVMEM

UBI volumes may be used to contain NVMEM bits, typically device MAC
addresses or wireless radio calibration data.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>

Documentation/devicetree/bindings/mtd/partitions/linux,ubi.yaml

@@ -59,6 +59,16 @@ examples:
                 ubi-volume-caldata {
                     volid = <2>;
                     volname = "rf";
+
+                    nvmem-layout {
+                        compatible = "fixed-layout";
+                        #address-cells = <1>;
+                        #size-cells = <1>;
+
+                        eeprom@0 {
+                            reg = <0x0 0x1000>;
+                        };
+                    };
                 };
             };
         };