Merge branch 'progarray_mapinmap_dump'

Yonghong Song says:

====================
The support to dump program array and map_in_map maps
for bpffs and bpftool is added. Patch #1 added bpffs support
and Patch #2 added bpftool support. Please see
individual patches for example output.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>