MFC r217499:

MFC r217499:
  Implement initial jumbo frame support for RTL8168/8111 C/D/E PCIe
  GbE controllers. It seems these controllers no longer support
  multi-fragmented RX buffers such that driver have to allocate
  physically contiguous buffers.

   o Retire RL_FLAG_NOJUMBO flag and introduce RL_FLAG_JUMBOV2 to
     mark controllers that use new jumbo frame scheme.
   o Configure PCIe max read request size to 4096 for standard frames
     and reduce it to 512 for jumbo frames.
   o TSO/checksum offloading is not supported for jumbo frames on
     these controllers. Reflect it to ioctl handler and driver
     initialization.
   o Remove unused rl_stats_no_timeout in softc.
   o Embed a pointer to structure rl_hwrev into softc to keep track
     of controller MTU limitation and remove rl_hwrev in softc since
     that information is available through a pointer to structure
     rl_hwrev.

  Special thanks to Realtek for donating sample hardwares which made
  this possible.

  H/W donated by:	Realtek Semiconductor Corp.

git-svn-id: svn://svn.freebsd.org/base/stable/8@218903 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f