Do our best to plug some memory leaks (VPD data, jumbo memory buffer,...).
Log if we cannot free because memory still in use[1].
Change locking to avoid ''acquiring duplicate lock of same
type: "network driver"'' and potential deadlock. Also seems to fix LOR #063.
[1] This change does not solve problems if buffers are still in use when
unloading if_sk.ko. There is ongoing work which will address jumbogram
allocations in a more general way.
PR: kern/75677 (with changes, no mii fixes in here)
Tested by: net, Antoine Brodin (slightly different version)
Approved by: rwatson (mentor)
MFC after: 5 days