libpdbg: Warn if default_backend() falls back to fake backend
libpdbg: Warn if default_backend() falls back to fake backend

Signed-off-by: Jordan Niethe <9a2a0dd028f3d72149898175729ca02ebb3d30fe@gmail.com>
Reviewed-by: Amitay Isaacs <a505e7c038746dbeb3edcd8d146dbd515432801f@ozlabs.org>

open-power/pdbg,open-power/pdbg,open-power/pdbg