cmd: Fix virtio command dependency

The 'virtio' command calls blk_common_cmd() which is only available
when CONFIG_HAVE_BLOCK_DEVICE is on. Fix the Kconfig dependency.
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NPriyanka Jain <priyanka.jain@nxp.com>

cmd/Kconfig

@@ -1345,6 +1345,7 @@ config CMD_PVBLOCK
 config CMD_VIRTIO
 	bool "virtio"
 	depends on VIRTIO
+	depends on HAVE_BLOCK_DEVICE
 	default y if VIRTIO
 	help
 	  VirtIO block device support