tty: hvc_vio: 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: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/hvc/hvc_vio.c

@@ -53,7 +53,7 @@
 
 static const char hvc_driver_name[] = "hvc_console";
 
-static struct vio_device_id hvc_driver_table[] = {
+static const struct vio_device_id hvc_driver_table[] = {
 	{"serial", "hvterm1"},
 #ifndef HVC_OLD_HVSI
 	{"serial", "hvterm-protocol"},