pc-bios/s390-ccw/virtio: Beautify the code for reading virtqueue configuration

It looks nicer if we separate the run_ccw() from the IPL_assert()
statement, and the error message should talk about "virtio device"
instead of "block device", since this code is nowadays used for
non-block (i.e. network) devices, too.

Message-Id: <20220704111903.62400-9-thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

pc-bios/s390-ccw/virtio.c

@@ -289,9 +289,8 @@ void virtio_setup_ccw(VDev *vdev)
             .num = 0,
         };
 
-        IPL_assert(
-            run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config), false) == 0,
-            "Could not get block device VQ configuration");
+        rc = run_ccw(vdev, CCW_CMD_READ_VQ_CONF, &config, sizeof(config), false);
+        IPL_assert(rc == 0, "Could not get virtio device VQ configuration");
         info.num = config.num;
         vring_init(&vdev->vrings[i], &info);
         vdev->vrings[i].schid = vdev->schid;