MFC r316541, r316544, and r320688 from HEAD to stable/11.
Fix a double free in ixgbe_rxeof()
Don't overwrite vf->flags variable at the end of ixgbe(4) ixgbe_add_vf()
ixgbe(4): Update HEAD (p3) to 3.2.12-k
- Support for X550EM devices.
- Support for Bypass adapters.
- Flow Director code moved to separate files
- SR-IOV code moved to separate files
- Netmap code moved to separate files
Sponsored by: Intel Corporation