Various fixes to stats:
- Read the counts of received, dropped, and transmitted management
  packets and add sysctl nodes for them.
- Fix the total octets received/transmitted to read all 64 bits of
  the counters.
- Add missing sysctl nodes for rlec, tncrs, fcruc, tor, and tot.
- Remove spurious spaces.

Reviewed by:	Eric Joyner @ Intel
MFC after:	1 week