bpf: Cleanup ftrace hash in bpf_trampoline_put

We need to release possible hash from trampoline fops object
before removing it, otherwise we leak it.

Fixes: 00963a2e ("bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20220802135651.1794015-1-jolsa@kernel.org