tty: hvcs: constify vio_device_id

vio_device_id are not supposed to change at runtime. All functions
working with vio_device_id provided by <asm/vio.h> work with
const vio_device_id. So mark the non-const structs as const.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/hvc/hvcs.c

@@ -675,7 +675,7 @@ static int khvcsd(void *unused)
 	return 0;
 }
 
-static struct vio_device_id hvcs_driver_table[] = {
+static const struct vio_device_id hvcs_driver_table[] = {
 	{"serial-server", "hvterm2"},
 	{ "", "" }
 };