crypto: virtio - constify features[] and id_table[]

features[] and id_table[] are not modified and can be made const to
allow the compiler to put them in read-only memory.

Before:
   text    data     bss     dec     hex filename
  11534    2056     160   13750    35b6 drivers/crypto/virtio/virtio_crypto_core.o

After:
   text    data     bss     dec     hex filename
  11630    1992     128   13750    35b6 drivers/crypto/virtio/virtio_crypto_core.o

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/virtio/virtio_crypto_core.c

@@ -498,11 +498,11 @@ free_vqs:
 }
 #endif
 
-static unsigned int features[] = {
+static const unsigned int features[] = {
 	/* none */
 };
 
-static struct virtio_device_id id_table[] = {
+static const struct virtio_device_id id_table[] = {
 	{ VIRTIO_ID_CRYPTO, VIRTIO_DEV_ANY_ID },
 	{ 0 },
 };