net: tcp: Add noinline_for_tracing annotation for tcp_drop_reason()

net: tcp: Add noinline_for_tracing annotation for tcp_drop_reason()

We previously hooked the tcp_drop_reason() function using BPF to monitor
TCP drop reasons. However, after upgrading our compiler from GCC 9 to GCC
11, tcp_drop_reason() is now inlined, preventing us from hooking into it.
To address this, it would be beneficial to make noinline explicitly for
tracing.

Link: https://lore.kernel.org/netdev/CANn89iJuShCmidCi_ZkYABtmscwbVjhuDta1MS5LxV_4H9tKOA@mail.gmail.com/
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Menglong Dong <menglong8.dong@gmail.com>
Link: https://patch.msgid.link/20241024093742.87681-3-laoar.shao@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>