crypto: ccree - remove set but not used variable 'du_size'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/crypto/ccree/cc_cipher.c: In function 'cc_setup_state_desc':
drivers/crypto/ccree/cc_cipher.c:536:15: warning:
 variable 'du_size' set but not used [-Wunused-but-set-variable]

commit 5c83e8ec ("crypto: ccree - fix FDE descriptor sequence")
involved this unused variable, so remove it.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>