hw: Do not include "exec/address-spaces.h" if it is not necessary

Code change produced with:
    $ git grep '#include "exec/address-spaces.h"' hw include/hw | \
      cut -d: -f-1 | \
      xargs egrep -L "(get_system_|address_space_)" | \
      xargs sed -i.bak '/#include "exec\/address-spaces.h"/d'

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20180528232719.4721-12-f4bug@amsat.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>