perf hist stdio: Do bounds check when printing callchains to avoid UB with new gcc versions

Do a simple bounds check to avoid this on new gcc versions:

  31    15.81 fedora:rawhide                : FAIL gcc version 15.0.1 20250225 (Red Hat 15.0.1-0) (GCC)
    In function 'callchain__fprintf_left_margin',
        inlined from 'callchain__fprintf_graph.constprop' at ui/stdio/hist.c:246:12:
    ui/stdio/hist.c:27:39: error: iteration 2147483647 invokes undefined behavior [-Werror=aggressive-loop-optimizations]
       27 |         for (i = 0; i < left_margin; i++)
          |                                      ~^~
    ui/stdio/hist.c:27:23: note: within this loop
       27 |         for (i = 0; i < left_margin; i++)
          |                     ~~^~~~~~~~~~~~~
    cc1: all warnings being treated as errors

Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>
(cherry picked from commit 2333cfa)
Signed-off-by: Andrea Righi <[email protected]>

Author: acmel

tools/perf/ui/stdio/hist.c

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <linux/string.h>
@@ -24,6 +25,9 @@ static size_t callchain__fprintf_left_margin(FILE *fp, int left_margin)
 	int i;
 	int ret = fprintf(fp, "            ");
 
+	if (left_margin > USHRT_MAX)
+		left_margin = USHRT_MAX;
+
 	for (i = 0; i < left_margin; i++)
 		ret += fprintf(fp, " ");