app/testpmd: enforce offload capabilities check

app/testpmd: enforce offload capabilities check

In the current design it was possible for offload to be set even though
the device is not supporting it. A warning message was printed instead.

This is a wrong behaviour, as application should set only the offloads
reported by the capabilities of the device.

This patch adds verification for the offloads being set and make sure
the offload configuration passed to the device always match its
capabilities.

Signed-off-by: Shahaf Shuler <shahafs@mellanox.com>
Acked-by: Wenzhuo Lu <wenzhuo.lu@intel.com>