qxl: add dev id to guest prints

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

hw/qxl.c

diff --git a/hw/qxl.c b/hw/qxl.c
index 3722f55..d55b68d 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -985,7 +985,8 @@
         break;
     case QXL_IO_LOG:
         if (d->guestdebug) {
-            fprintf(stderr, "qxl/guest: %s", d->ram->log_buf);
+            fprintf(stderr, "qxl/guest-%d: %ld: %s", d->id,
+                    qemu_get_clock_ns(vm_clock), d->ram->log_buf);
         }
         break;
     case QXL_IO_RESET: