vl.c: select_machine(): add selected machine type to error message Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Michael Tokarev <mjt@tls.msk.ru> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>