even initialized it, but it never used it.
- Use callout_*() to manage the callout.
- Use m_devget() to copy data out of the rx buffers rather than doing it
all by hand.
- Use m_getcl() to allocate mbuf clusters rather than doing it all by hand.
- Don't free the software descriptor for a rx ring entry if we can't
allocate an mbuf cluster for it. We left a dangling pointer and never
reallocated the entry anyway. OpenBSD's code (from which this was
derived) has the same bug.
Tested by: NO ONE (despite repeated requests)
Reviewed by: wpaul (5)