Amazon DPDK 19.05 ENA patches

[talawahtech]

This PR is to add the set of DPDK patches that Amazon backported to DPDK 19.05 for their ENA driver. https://github.com/amzn/amzn-drivers/tree/ena_linux_2.6.1/userspace/dpdk/19.05

Note that patch 0004-net-ena-fix-L4-checksum-Tx-offload.patch is a duplicate and was therefore removed.

It should also be noted that going forward Amazon has switched to a policy of only backporting patches for LTS releases, e.g 19.11.x, 20.11.x.