v3dv: VK_KHR_display extension support
Adds support for the VK_KHR_display extension to the v3dv driver.
Work initially started by @dmrlawson
Closes: #3692 (closed)
Tested on vkcube, vkQuake2 and a number of Sascha Willems examples. @bluestang2006 and @vanfanel have done some testing on RetroArch and DuckStation. @dmrlawson has run it with Lakka.
This is my first merge request to Mesa so please let me know if I've missed anything.
Edited by Steven Houston