Revert "main: Add Vulkan device selection for Mesa drivers"
This reverts commit 69b121b0.
https://docs.mesa3d.org/envvars.html#envvar-DRI_PRIME clearly says: "It applies to OpenGL and Vulkan"
This reverts commit 69b121b0.
https://docs.mesa3d.org/envvars.html#envvar-DRI_PRIME clearly says: "It applies to OpenGL and Vulkan"