test/crypto: fix armv8 virtual PMD autotest

test/crypto: fix armv8 virtual PMD autotest

armv8 cryptodev virtual PMD autotest failed with output:
CRYPTODEV: [CRYPTODEV_NAME_ARMV8_CRYPTO_PMD]
armv8_crypto_pmd_qp_create_processed_ops_ring() line 210:
Unable to reuse existing ring armv8_crypto_pmd_0_qp_0 for processed ops
CRYPTODEV: rte_cryptodev_stop() line 942:
Device with dev_id=0 already stopped
+ TestCase [ 0] : test_AES_chain_armv8_all failed

This is due to the ring size used in ut_setup is bigger than that used
in testsuite_setup.
Fix this issue by enlarge ring size used in testsuite_setup accordingly.

Fixes: 24054e3640a2 ("test/crypto: use separate session mempools")
Cc: stable@dpdk.org
Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
Reviewed-by: Gavin Hu <gavin.hu@arm.com>