bpf: Call maybe_wait_bpf_programs() only once for generic_map_update_batch()

Just like commit 9087c6ff ("bpf: Call maybe_wait_bpf_programs() only
once from generic_map_delete_batch()"), there is also no need to call
maybe_wait_bpf_programs() for each update in batched update, so only
call it once in generic_map_update_batch().

Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231208102355.2628918-3-houtao@huaweicloud.com


Signed-off-by: Alexei Starovoitov <ast@kernel.org>