virtio: Fix indentation of VIRTIO_MMIO

VIRTIO_MMIO config option block starts with a space, fix that.
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/virtio/Kconfig

@@ -63,7 +63,7 @@ config VIRTIO_INPUT
 
 	 If unsure, say M.
 
- config VIRTIO_MMIO
+config VIRTIO_MMIO
 	tristate "Platform bus driver for memory mapped virtio devices"
 	depends on HAS_IOMEM && HAS_DMA
 	select VIRTIO