bpf: net: Avoid do_tcp_getsockopt() taking sk lock when called from bpf

Similar to the earlier commit that changed sk_setsockopt() to
use sockopt_{lock,release}_sock() such that it can avoid taking
lock when called from bpf.  This patch also changes do_tcp_getsockopt()
to use sockopt_{lock,release}_sock() 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/20220902002821.2889765-1-kafai@fb.com


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