Also note to add xhci(4) to kernel configuration to utilize USB 3.0

Approved by:	markj
Mention axge(4)

Approved by:	kevlo
DragonFly 3.6.0 released.
Pull in r195558 from upstream clang trunk:

  Fix a SSE2 intrinsics typo

  Full discourse at:

   http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20131104/092514.html
   http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-November/068124.html

  Patch by Dimitry Andric and Alexey Dokuchaev!

Reported by:	danfe
MFC after:	3 days