sysemu: Move the VMChangeStateEntry typedef to qemu/typedefs.h

sysemu: Move the VMChangeStateEntry typedef to qemu/typedefs.h

In my "build everything" tree, changing sysemu/sysemu.h triggers a
recompile of some 1800 out of 6600 objects (not counting tests and
objects that don't depend on qemu/osdep.h, down from 5400 due to the
previous commit).

Several headers include sysemu/sysemu.h just to get typedef
VMChangeStateEntry.  Move it from sysemu/sysemu.h to qemu/typedefs.h.
Spell its structure tag the same while there.  Drop the now
superfluous includes of sysemu/sysemu.h from headers.

Touching sysemu/sysemu.h now recompiles some 1100 objects.
qemu/uuid.h also drops from 1800 to 1100, and
qapi/qapi-types-run-state.h from 5000 to 4400.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190812052359.30071-29-armbru@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>