bpf: Fix array bounds error with may_goto

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix array bounds error with may_goto

may_goto uses an additional 8 bytes on the stack, which causes the

interpreters[] array to go out of bounds when calculating index by

stack_size.

1. If a BPF program is rewritten, re-evaluate the stack size. For non-JIT

cases, reject loading directly.

2. For non-JIT cases, calculating interpreters[idx] may still cause

out-of-bounds array access, and just warn about it.

3. For jit_requested cases, the execution of bpf_func also needs to be

warned. So move the definition of function __bpf_prog_ret0_warn out of

the macro definition CONFIG_BPF_JIT_ALWAYS_ON.