cbfstool: process cbfs_payload_segment(s) in host byte order

The printing routines of the cbfs_payload_segment assumed the type
could be accessed in host order. Each of the fields need to be
converted to the host order before inspecting the fields. In addition,
this removes all the ntoh*() calls while processing the
cbfs_payload_segment structures.

cbfstool would crash adding entries or just printing entries
containing a payload when -v was passed on the command line.

Change-Id: Iff41c64a99001b9e3920e2e26828c5fd6e671239
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/6498
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <gaumless@gmail.com>