MAINTAINER: samsung: document dtbs_check requirement for Samsung

Samsung ARM/ARM64 SoCs (including legacy S3C64xx and S5PV210) are also
expected not to bring any new dtbs_check warnings.  In fact this have
been already enforced and tested since few release.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Link: https://lore.kernel.org/r/20230723131924.78190-3-krzysztof.kozlowski@linaro.orgSigned-off-by: Arnd Bergmann <arnd@arndb.de>

MAINTAINERS

@@ -2634,6 +2634,7 @@ R:	Alim Akhtar <alim.akhtar@samsung.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 L:	linux-samsung-soc@vger.kernel.org
 S:	Maintained
+P:	Documentation/process/maintainer-soc-clean-dts.rst
 Q:	https://patchwork.kernel.org/project/linux-samsung-soc/list/
 B:	mailto:linux-samsung-soc@vger.kernel.org
 C:	irc://irc.libera.chat/linux-exynos