radv: Add RADV_DEBUG=nort

This makes vkCmdTraceRaysKHR and ray queries no-ops and is useful
for triaging GPU hangs with raytracing.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23603>

src/amd/vulkan/radv_instance.c

@@ -77,6 +77,7 @@ static const struct debug_control radv_debug_options[] = {
    {"extra_md", RADV_DEBUG_EXTRA_MD},
    {"nogpl", RADV_DEBUG_NO_GPL},
    {"videoarraypath", RADV_DEBUG_VIDEO_ARRAY_PATH},
+   {"nort", RADV_DEBUG_NO_RT},
    {NULL, 0}};
 
 const char *