crypto: inside-secure - Fix sizeof() mismatch

An incorrect sizeof() is being used, sizeof(priv->ring[i].rdr_req) is
not correct, it should be sizeof(*priv->ring[i].rdr_req). Note that
since the size of ** is the same size as * this is not causing any
issues.

Addresses-Coverity: ("Sizeof not portable (SIZEOF_MISMATCH)")
Fixes: 9744fec9 ("crypto: inside-secure - remove request list to improve performance")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>