This adds a new "-d" switch to "info mtree" to print dispatch tree
internals.

This changes the way "-f" is handled - it prints now flat views and
associated address spaces.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Message-Id: <20170921085110.25598-15-aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>