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

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.com
Signed-off-by: Rob Herring <robh@kernel.org>