target-s390x: Fix debug output

Commit 71e470886fb6092504503a5fe41092ace71c096c (target-s390x: fix
style) renamed the cpu_s390x_handle_mmu_fault() argument from _vaddr to
orig_vaddr. Update the debug output code.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/target-s390x/helper.c b/target-s390x/helper.c
index d693a10..e62c93e 100644
--- a/target-s390x/helper.c
+++ b/target-s390x/helper.c
@@ -387,7 +387,7 @@
     int prot;
 
     DPRINTF("%s: address 0x%" PRIx64 " rw %d mmu_idx %d\n",
-            __func__, _vaddr, rw, mmu_idx);
+            __func__, orig_vaddr, rw, mmu_idx);
 
     orig_vaddr &= TARGET_PAGE_MASK;
     vaddr = orig_vaddr;