tools: bpftool: use more common tag format

Program tag is usually displayed as string of bytes without
any separators (e.g. as "aa5520b1090cfeb6" vs MAC addr-like
format bpftool uses currently: "aa:55:20:b1:09:0c:fe:b6").
Make bptfool use the more common format both for displaying
the tag and selecting the program by tag.

This was pointed out in review but I misunderstood the comment.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>