venus: handle VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT

venus: handle VK_QUERY_TYPE_PRIMITIVES_GENERATED_EXT

This change adds some docs for the query size, and has been tested with
dEQP-VK.transform_feedback.primitives_generated_query.* on supported
implementations.

Fixes: 8f7b5bf34b4 ("venus: add VK_EXT_primitives_generated_query support")

Signed-off-by: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Juston Li <justonli@google.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19684>
(cherry picked from commit f7d7e558c958d4057cf88dfa37f80d150d62d87f)