perf tools: Ditch rtrim(), use skip_spaces() to get closer to the kernel

No change in behaviour, just using the same kernel idiom for such
operation.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: André Goddard Rosa <andre.goddard@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-a85lkptkt0ru40irpga8yf54@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/ui/stdio/hist.c

@@ -516,7 +516,7 @@ static int hist_entry__hierarchy_fprintf(struct hist_entry *he,
 		 * dynamic entries are right-aligned but we want left-aligned
 		 * in the hierarchy mode
 		 */
-		printed += fprintf(fp, "%s%s", sep ?: "  ", ltrim(buf));
+		printed += fprintf(fp, "%s%s", sep ?: "  ", skip_spaces(buf));
 	}
 	printed += putc('\n', fp);