bpf: Add batched ops support for percpu array

Uses the already in-place infrastructure provided by the
'generic_map_*_batch' functions.

No tweak was needed as it transparently handles the percpu variant.

As arrays don't have delete operations, let it return a error to
user space (default behaviour).
Suggested-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210424214510.806627-2-pctammela@mojatatu.com

kernel/bpf/arraymap.c

@@ -698,6 +698,8 @@ const struct bpf_map_ops percpu_array_map_ops = {
 	.map_delete_elem = array_map_delete_elem,
 	.map_seq_show_elem = percpu_array_map_seq_show_elem,
 	.map_check_btf = array_map_check_btf,
+	.map_lookup_batch = generic_map_lookup_batch,
+	.map_update_batch = generic_map_update_batch,
 	.map_set_for_each_callback_args = map_set_for_each_callback_args,
 	.map_for_each_callback = bpf_for_each_array_elem,
 	.map_btf_name = "bpf_array",