mem: stop searching a parent vma if we found one

A parent vma can be only one.

Fixes: 57d25e7c ("mm: fix expression to determine which vma-s can be shared")
Reported-by: Filipe Brandenburger <filbranden@google.com>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-restore.c

@@ -261,6 +261,8 @@ static int map_private_vma(pid_t pid, struct vma_area *vma, void **tgt_addr,
 		pr_info("COW 0x%016"PRIx64"-0x%016"PRIx64" 0x%016"PRIx64" vma\n",
 			vma->e->start, vma->e->end, vma->e->pgoff);
 		paddr = decode_pointer(p->premmaped_addr);
+
+		break;
 	}
 
 	*pvma = p;