perf tools: Try to build Documentation when installing

There's a portion in the "perf list" output refering to the exact
specification of raw hardware events.

Since this description is in the perf-list manpage, try to build and
install the man pages, warning the user when that is not possible
due to missing packages (xmlto and asciidoc).

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/n/tip-ij71ysszkdvz3fy3wr331bke@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 2fe1587..3a3efcf 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1081,7 +1081,7 @@
 		printf("  %-50s [%s]\n",
 		       "cpu/t1=v1[,t2=v2,t3 ...]/modifier",
 		       event_type_descriptors[PERF_TYPE_RAW]);
-		printf("   (see 'perf list --help' on how to encode it)\n");
+		printf("   (see 'man perf-list' on how to encode it)\n");
 		printf("\n");
 
 		printf("  %-50s [%s]\n",