examples/ipsec-secgw: add check for unprotected port mask
examples/ipsec-secgw: add check for unprotected port mask

Usage of unprotected port mask without any configured SA inbound, will
cause use of uninitialized SA context, so disallow such configuration.

Signed-off-by: Volodymyr Fialko <728c6fdfa926c8a5981c24cb0f1ba9da847df5e2@marvell.com>
Acked-by: Anoob Joseph <3ccb4777bd2856f4d9127f25efe6455b1a791ba2@marvell.com>

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