media: dt-bindings: ak7375: Convert to DT schema

commit 6d801f89 upstream

Convert DT bindings document for AKM AK7375 VCM to DT schema
format and add an example.

Signed-off-by: Yassine Oudjana <y.oudjana@protonmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Umang Jain <umang.jain@ideasonboard.com>