net: Rename ->stream_memory_read to ->sock_is_readable

[ Upstream commit 7b50ecfc ]

The proto ops ->stream_memory_read() is currently only used
by TCP to check whether psock queue is empty or not. We need
to rename it before reusing it for non-TCP protocols, and
adjust the exsiting users accordingly.

Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211008203306.37525-2-xiyou.wangcong@gmail.com


Stable-dep-of: 2660a544 ("net: Fix TOCTOU issue in sk_is_readable()")
Signed-off-by: Sasha Levin <sashal@kernel.org>