crypto: spacc - Fix off by one in spacc_isenabled()

The spacc->config.modes[] array has CRYPTO_MODE_LAST number of elements
so this > comparison should be >= to prevent an out of bounds access.

Fixes: c8981d92 ("crypto: spacc - Add SPAcc Skcipher support")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>