vio: move to_vio_dev() to use container_of_const()

The driver core is changing to pass some pointers as const, so move
to_vio_dev() to use container_of_const() to handle this change.
to_vio_dev() now properly keeps the const-ness of the pointer passed
into it, while as before it could be lost.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230111113018.459199-9-gregkh@linuxfoundation.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>