bpf: Fix bpf_trampoline_{,un}link_cgroup_shim ifdef guards

bpf: Fix bpf_trampoline_{,un}link_cgroup_shim ifdef guards

They were updated in kernel/bpf/trampoline.c to fix another build
issue. We should to do the same for include/linux/bpf.h header.

Fixes: 44f6c3fb668b ("bpf: fix lsm_cgroup build errors on esoteric configs")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220720155220.4087433-1-sdf@google.com