tools/bpftool: re-organize newline printing for map listing

Let's move the final newline printing in show_map_close_plain() at
the end of the function because it looks correct and consistent with
prog.c. Also let's do related changes for the line which prints
pinned file name.

Signed-off-by: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Reviewed-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: Alexei Starovoitov <ast@kernel.org>