MFC r242425:

MFC r242425:
  Remove TCP/UDP checksum offloading feature for IP fragmented
  datagrams.  Traditionally upper stack fragmented packets without
  computing TCP/UDP checksum and these datagrams were passed to
  driver.  But there are chances that other packets slip into the
  interface queue in SMP world. If this happens firmware running on
  MIPS 4000 processor in the controller would see mixed packets and
  it shall send out corrupted packets.
  While I'm here simplify checksum offloading setup.

git-svn-id: svn://svn.freebsd.org/base/stable/8@242740 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f