selftests/bpf: fix inet_csk_accept prototype in test_sk_storage_tracing.c

Recent kernel change ([0]) changed inet_csk_accept() prototype. Adapt
progs/test_sk_storage_tracing.c to take that into account.

[0] 92ef0fd55ac8 ("net: change proto and proto_ops accept type")

Signed-off-by: Andrii Nakryiko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

tools/testing/selftests/bpf/progs/test_sk_storage_tracing.c

···
 }
 
 SEC("fexit/inet_csk_accept")
-int BPF_PROG(inet_csk_accept, struct sock *sk, int flags, int *err, bool kern,
+int BPF_PROG(inet_csk_accept, struct sock *sk, struct proto_accept_arg *arg,
 	     struct sock *accepted_sk)
 {
 	set_task_info(accepted_sk);