MFC r204155,204219:

MFC r204155,204219:
r204155:
  Increase PCIe maximuim read request size to 2048. Because re(4) uses
  Tx DMA burst size 2048, I beleive PCIe maximum read request size
  also should match to the value of Tx DMA burst size. With this
  change I can get more than 800Mbps for TCP bulk transfers.
  Previously I was not able to get more than 700Mbps. If I enable TSO
  it now shows 927Mbps.

r204219:
  Add TSO on VLANs. Because re(4) has a TSO limitation for jumbo
  frame, make sure to update VLAN capabilities whenever jumbo frame
  is configured.
  While I'm here rearrange interface capabilities configuration. The
  controller requires VLAN hardware tagging to make TSO work on VLANs
  so explicitly check this requirement.

git-svn-id: svn://svn.freebsd.org/base/stable/8@205526 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f