bpf: fix bpf_perf_event_read() loop upper bound

Verifier rejects programs incorrectly.

Fixes: 35578d7 ("bpf: Implement function bpf_perf_event_read()")
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Wei-Chun Chao <weichunc@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

kernel/bpf/verifier.c

@@ -853,7 +853,7 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id)
 	if (!map)
 		return 0;
 
-	for (i = 0; i <= ARRAY_SIZE(func_limit); i++) {
+	for (i = 0; i < ARRAY_SIZE(func_limit); i++) {
 		bool_map = (map->map_type == func_limit[i].map_type);
 		bool_func = (func_id == func_limit[i].func_id);
 		/* only when map & func pair match it can continue.