venus: check vn_renderer_info::vk_xml_version
When crosvm does not support venus, it still advertises
VIRGL_RENDERER_CAPSET_VENUS but provides no or zeroed capset data.
vk_xml_version will be zero.
It is a good idea to verify vk_xml_version anyway.
v2: print required version suggested by Ryan
Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Ryan Neph <ryanneph@google.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10192>