Include migration/qemu-file-types.h a lot less

Include migration/qemu-file-types.h a lot less

In my "build everything" tree, changing migration/qemu-file-types.h
triggers a recompile of some 2600 out of 6600 objects (not counting
tests and objects that don't depend on qemu/osdep.h).

The culprit is again hw/hw.h, which supposedly includes it for
convenience.

Include migration/qemu-file-types.h only where it's needed.  Touching
it now recompiles less than 200 objects.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190812052359.30071-10-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>