examples/l2fwd-crypto: skip device not supporting operation

examples/l2fwd-crypto: skip device not supporting operation

When a crypto device does not support an algorithm, it is skipped
and not used. However, when it does support it, but not the rest
of the parameters (IV, key, AAD sizes...), application stops.
Instead, the device should be skipped and the search of a suitable
device should continue.

Fixes: a061e50a0d97 ("examples/l2fwd-crypto: fix ambiguous input key size")
Cc: stable@dpdk.org
Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Acked-by: Fiona Trahe <fiona.trahe@intel.com>