dt-bindings: hwinfo: samsung,exynos-chipid: add exynosautov920 compatible

Add "samsung,exynosautov920-chipid" compatible string to binding document.

Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Link: https://lore.kernel.org/r/20231115095609.39883-9-jaewon02.kim@samsung.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>