tools: bpftool: remove blank line after btf_id when listing programs

Commit 569b0c77

 ("tools/bpftool: show btf id in program information")
made bpftool print an empty line after each program entry when listing
the BPF programs loaded on the system (plain output). This is especially
confusing when some programs have an associated BTF id, and others
don't. Let's remove the blank line.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>