vulkan/wsi: Add modifiers support to wsi_create_native_image

vulkan/wsi: Add modifiers support to wsi_create_native_image

This involves extending our fake extension a bit to allow for additional
querying and passing of modifier information.  The added bits are
intended to look a lot like the draft of VK_EXT_image_drm_format_modifier.
Once the extension gets finalized, we'll simply transition all of the
structs used in wsi_common to the real extension structs.

Reviewed-by: Daniel Stone <daniels@collabora.com>