qapi: Fix generation of 'size' builtin type We were missing the 'size' builtin type (which means that QAPI using [ 'size' ] would fail to compile). Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>