perf tools: Add the bash completion for listing subsubcommands of perf timechart

The bash completion does not support listing subsubcommands for 'perf
timechart <TAB>', so fix it.

Example:

Before this patch:

$ perf timechart <TAB>
$

As shown above, the subsubcommands of perf timechart does not come out.

After this patch:

$ perf timechart <TAB>
record

As shown above, the subsubcommands of perf timechart can come out now.

Signed-off-by: Yunlong Song <[e-mail]>
Tested-by: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-timechart.c

···
 		     parse_time),
 	OPT_END()
 	};
-	const char * const timechart_usage[] = {
+	const char * const timechart_subcommands[] = { "record", NULL };
+	const char *timechart_usage[] = {
 		"perf timechart [<options>] {record}",
 		NULL
 	};
···
 		"perf timechart record [<options>]",
 		NULL
 	};
-	argc = parse_options(argc, argv, timechart_options, timechart_usage,
-			PARSE_OPT_STOP_AT_NON_OPTION);
+	argc = parse_options_subcommand(argc, argv, timechart_options, timechart_subcommands,
+			timechart_usage, PARSE_OPT_STOP_AT_NON_OPTION);
 
 	if (tchart.power_only && tchart.tasks_only) {
 		pr_err("-P and -T options cannot be used at the same time.\n");

tools/perf/perf-completion.sh

···
 		__perfcomp_colon "$evts" "$cur"
 	else
 		# List subcommands for perf commands
-		if [[ $prev_skip_opts == @(kvm|kmem|mem|lock|sched|data|help|script|test) ]]; then
+		if [[ $prev_skip_opts == @(kvm|kmem|mem|lock|sched|data|help|script|test|timechart) ]]; then
 			subcmds=$($cmd $prev_skip_opts --list-cmds)
 			__perfcomp_colon "$subcmds" "$cur"
 		fi