There are many vendors (including some internal Microsoft projects) with drivers that are not in the DPDK tree. Breaking them is not something that should be done, and certainly not in a release that claims API/ABI compatibility.
Although these fields should not have been exposed to user in normal header files, you can't just remove them now. Please revert this commit before 20.02 final release. A better solution (like __rte_internal) can be added in the 21.11 release.
