venus: Simplify vn_GetPhysicalDeviceProperties2

Reduce approximately 220 lines to 80.

Signed-off-by: Chad Versace <chadversary@chromium.org>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>
Reviewed-by: Ryan Neph <ryanneph@google.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18000>