Similar to the earlier patch that changes sk_getsockopt() to
take the sockptr_t argument .  This patch also changes
do_tcp_getsockopt() to take the sockptr_t argument such that
a latter patch can make bpf_getsockopt(SOL_TCP) to reuse
do_tcp_getsockopt().
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002815.2889332-1-kafai@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>