nir/print: Use 4-space indentation

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23564>

src/compiler/nir/nir_print.c

@@ -40,7 +40,7 @@ static void
 print_indentation(unsigned levels, FILE *fp)
 {
    for (unsigned i = 0; i < levels; i++)
-      fprintf(fp, "\t");
+      fprintf(fp, "    ");
 }
 
 typedef struct {