examples/l2fwd-crypto: check return value on IV size check
examples/l2fwd-crypto: check return value on IV size check

IV size parameter is checked through a function,
but its return value was not checked.

Fixes: 0fbd75a99fc9 ("cryptodev: move IV parameters to session")
Fixes: acf8616901b5 ("cryptodev: add auth IV")
Fixes: 2661f4fbe93d ("examples/l2fwd-crypto: add AEAD parameters")
Cc: stable@dpdk.org

Signed-off-by: Pablo de Lara <28355d9cfe41bb8148aea0fb24f47aae8f4217a1@intel.com>
Acked-by: Fiona Trahe <7ba562cc372916cd557d0be347608f8b4da4f746@intel.com>

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