DeviceTree updates for v4.18: - Sync dtc with upstream version v1.4.6-21-g84e414b0b5bc. This adds new warnings which are either fixed or disabled by default (enabled with W=1). - Validate an untrusted offset in DT overlay function update_usages_of_a_phandle_reference - Fix a use after free error of_platform_device_destroy - Fix an off by 1 string errors in unittest - Avoid creating a struct device for OPP nodes - Update DT specific submitting-patches.txt with patch content and subject requirements. - Move some bindings to their proper subsystem locations - Add vendor prefixes for Kaohsiung, SiFive, Avnet, Wi2Wi, Logic PD, and ArcherMind - Add documentation for "no-gpio-delays" property in FSI bus GPIO master - Add compatible for r8a77990 SoC ravb ethernet block - More wack-a-mole removal of 'status' property in examples