bpftool: Replace sizeof(arr)/sizeof(arr[0]) with ARRAY_SIZE macro

Use the ARRAY_SIZE macro and make the code more compact.
Signed-off-by: Rongguang Wei <weirongguang@kylinos.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220726093045.3374026-1-clementwei90@163.com

tools/bpf/bpftool/prog.c

@@ -1962,7 +1962,7 @@ static int profile_parse_metrics(int argc, char **argv)
 	int selected_cnt = 0;
 	unsigned int i;
 
-	metric_cnt = sizeof(metrics) / sizeof(struct profile_metric);
+	metric_cnt = ARRAY_SIZE(metrics);
 
 	while (argc > 0) {
 		for (i = 0; i < metric_cnt; i++) {