dt-bindings: media: nokia,smia: eliminate yamllint warnings

Eliminate the following yamllint warnings:
./Documentation/devicetree/bindings/media/i2c/mipi-ccs.yaml
:4:1: [error] missing document start "---" (document-start)
:29:9: [warning] wrong indentation: expected 10 but found 8 (indentation)
:32:9: [warning] wrong indentation: expected 10 but found 8 (indentation)
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20201207042400.1498-3-thunder.leizhen@huawei.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/media/i2c/mipi-ccs.yaml

 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
 # Copyright (C) 2014--2020 Intel Corporation
-
+%YAML 1.2
+---
 $id: http://devicetree.org/schemas/media/i2c/mipi-ccs.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
@@ -26,11 +27,11 @@ properties:
   compatible:
     oneOf:
       - items:
-        - const: mipi-ccs-1.1
-        - const: mipi-ccs
+          - const: mipi-ccs-1.1
+          - const: mipi-ccs
       - items:
-        - const: mipi-ccs-1.0
-        - const: mipi-ccs
+          - const: mipi-ccs-1.0
+          - const: mipi-ccs
       - const: nokia,smia
 
   reg: