bpf: Add bpf_get_func_ip kprobe helper for multi kprobe link

Adding support to call bpf_get_func_ip helper from kprobe
programs attached by multi kprobe link.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-5-jolsa@kernel.org