test/crypto: fix max length for raw data path
test/crypto: fix max length for raw data path

Update the calculation of the max length needed when converting mbuf to
data vec in partial digest test case. This update make sure the enough
vec buffers are allocated for the appended digest in sgl op for raw
datapath api.

Fixes: 4868f6591c6f ("test/crypto: add cases for raw datapath API")
Cc: stable@dpdk.org

Signed-off-by: Kai Ji <e209f74ea3428a187ef98c7554e3872af2c59055@intel.com>
Acked-by: Akhil Goyal <c3c9da6f7a1dc963875aa67cfd85a4c94f75d526@marvell.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk