BACKPORT: x86/cfi,bpf: Fix bpf_struct_ops CFI

BPF struct_ops uses __arch_prepare_bpf_trampoline() to write
trampolines for indirect function calls. These tramplines much have
matching CFI.

In order to obtain the correct CFI hash for the various methods, add a
matching structure that contains stub functions, the compiler will
generate correct CFI which we can pilfer for the trampolines.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231215092707.566977112@infradead.org


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

Bug: 452811419
Change-Id: I28d38038dbdde5d22b0fd3831f4a47c1f5f03408
(cherry picked from commit 2cd3e377)
[liwei: fix some conflicts due to missing dependencies]
Signed-off-by: wei li <sirius.liwei@honor.corp-partner.google.com>