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/util/pmu.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/list.h>
 #include <linux/compiler.h>
+#include <linux/string.h>
 #include <sys/types.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -1339,7 +1340,7 @@ static void wordwrap(char *s, int start, int max, int corr)
 			break;
 		s += wlen;
 		column += n;
-		s = ltrim(s);
+		s = skip_spaces(s);
 	}
 }