venus: refactor vn_cmd_add_query_feedback and miscs

venus: refactor vn_cmd_add_query_feedback and miscs

There's no functional changes:
1. remove unused function arg and use snake case
2. do early return for direct recording (avoid dup feedback checks)
3. use vk_alloc instead of vk_zalloc if applicable
4. move local struct closer to usage, and use assignment
5. convert secondary cmd in_render_pass condition check to assert
6. avoid redundant list_del upon freeing up

Signed-off-by: Yiwei Zhang <zzyiwei@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24009>