test/crypto: fix auth-cipher compare length in OOP

test/crypto: fix auth-cipher compare length in OOP

For out-of-place operations, comparing expected ciphertext with
the operation result should skip cipher_offset bytes, as those
will not be copied from source to the destination buffer, making
the tests fail.

Fixes: 02ed7b3871d6 ("test/crypto: add SNOW3G test cases for auth-cipher")
Cc: stable@dpdk.org
Signed-off-by: Kai Ji <kai.ji@intel.com>
Signed-off-by: Damian Nowak <damianx.nowak@intel.com>
Acked-by: Fan Zhang <roy.fan.zhang@intel.com>