dt-bindings:iio:adc:sprd,sc2720-adc yaml conversion.

I changed the name to reflect a specific part in line with normal
naming conventions. If there is a particularly strong reason to
keep the wild cards let me know.

Otherwise this was a fairly simple conversion as part of converting
all the IIO bindings to yaml.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Orson Zhai <orsonzhai@gmail.com>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Link: https://lore.kernel.org/r/20200909175946.395313-7-jic23@kernel.org

Documentation/devicetree/bindings/iio/adc/sprd,sc2720-adc.yaml

@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/sprd,sc2720-adc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Spreadtrum SC27XX series PMICs ADC binding
+
+maintainers:
+  - Baolin Wang <baolin.wang7@gmail.com>
+
+description:
+  Supports the ADC found on these PMICs.
+
+properties:
+  compatible:
+    enum:
+      - sprd,sc2720-adc
+      - sprd,sc2721-adc
+      - sprd,sc2723-adc
+      - sprd,sc2730-adc
+      - sprd,sc2731-adc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  "#io-channel-cells":
+    const: 1
+
+  hwlocks:
+    maxItems: 1
+
+  nvmem-cells:
+    maxItems: 2
+
+  nvmem-cell-names:
+    items:
+      - const: big_scale_calib
+      - const: small_scale_calib
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - "#io-channel-cells"
+  - hwlocks
+  - nvmem-cells
+  - nvmem-cell-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    pmic {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        adc@480 {
+            compatible = "sprd,sc2731-adc";
+            reg = <0x480>;
+            interrupt-parent = <&sc2731_pmic>;
+            interrupts = <0 IRQ_TYPE_LEVEL_HIGH>;
+            #io-channel-cells = <1>;
+            hwlocks = <&hwlock 4>;
+            nvmem-cells = <&adc_big_scale>, <&adc_small_scale>;
+            nvmem-cell-names = "big_scale_calib", "small_scale_calib";
+        };
+    };
+...