tools, bpf_asm: Hard error on out of range jumps

Per discussion at [0] this was originally introduced as a warning due
to concerns about breaking existing code, but a hard error probably
makes more sense, especially given that concerns about breakage were
only speculation.

  [0] https://lore.kernel.org/bpf/c964892195a6b91d20a67691448567ef528ffa6d.camel@linux.ibm.com/T/#t



Signed-off-by: Ian Denhardt <ian@zenhack.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/bpf/a6b6c7516f5d559049d669968e953b4a8d7adea3.1614201868.git.ian@zenhack.net