[S390] add MACHINE_IS_LPAR flag

Introduce the MACHINE_IS_LPAR flag for code that should only be
executed if Linux is running in an LPAR.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 35dfc3c..232ef04 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -534,7 +534,7 @@
 
 	if ((bufnr != q->last_move) || q->qdio_error) {
 		q->last_move = bufnr;
-		if (!is_thinint_irq(q->irq_ptr) && !MACHINE_IS_VM)
+		if (!is_thinint_irq(q->irq_ptr) && MACHINE_IS_LPAR)
 			q->u.in.timestamp = get_usecs();
 		return 1;
 	} else