Major update to drm(4) code in OpenBSD-current (to linux 6.18.16)

In an unusually extensive commit, Jonathan Gray (jsg@) has upgraded the drm(4) (Direct Rendering Manager) subsystem in OpenBSD-current.

Coming at this point in the development cycle, this foreshadows what will be in the upcoming OpenBSD 7.9 release (yes, we're aware that link does not work yet).

Also worth noting is Jonathan's note in the commit message,

Thanks to the OpenBSD Foundation for sponsoring this work.

Please take this as a reminder that the OpenBSD Foundation supports important work on our favorite operating system and that supporting them will help future development of all kinds.