app/test-crypto-perf: fix double allocation of memory

app/test-crypto-perf: fix double allocation of memory

The field, 'cipher_iv.data' is allocated twice when cipher is not null.
Ideally the allocation should depend only on the field
'cperf_options.cipher_iv_sz'. This will make sure this code path gets
valid for ciphers which doesn't require IV.

Fixes: 0fbd75a99fc9 ("cryptodev: move IV parameters to session")
Cc: stable@dpdk.org
Signed-off-by: Akash Saxena <akash.saxena@caviumnetworks.com>
Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
Acked-by: Akhil Goyal <akhil.goyal@nxp.com>