zink/kopper: don't use generated include in kopper interface

this causes build race conditions

Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15830>

src/gallium/frontends/dri/kopper.c

@@ -30,7 +30,7 @@
 #include "state_tracker/st_context.h"
 #include "os/os_process.h"
 #include "zink/zink_public.h"
-#include "zink/zink_instance.h"
+#include "zink/zink_kopper.h"
 #include "driver_trace/tr_screen.h"
 
 #include "dri_screen.h"