spi: dt-bindings: samsung: Add Exynos850 SPI

Document samsung,exynos850-spi compatible which will be used on
Exynos850 SoC. Exynos850 doesn't have ioclk, so only two clocks are
needed (bus clock and functional SPI clock).

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://msgid.link/r/20240120012948.8836-3-semen.protsenko@linaro.org


Signed-off-by: Mark Brown <broonie@kernel.org>