gallium/iris: add yuv dmabuf formats support

This series of patches is try to fix a dmabuf importing problem when running test "weston-simple-dmabuf-drm --import-format=NV12" on ICL with iris enabled.

adds a few numbers of yuv formats, such as nv12, yu12, yv12 etc, in eglQueryDmaBufFormatsEXT for dmabuf import support. removes the allocate_aux case from iris. fixes some bugs