linux-yocto/3.10: genericx86 meta data factoring

Updating the 3.10 meta branch to import the following commits from Darren
Hart:

   285f93b meta/common-pc-64: Add USB 3.0 support
   75072e4 meta/common-pc*: Refactor common-pc-64 to reuse common-pc drivers
   da06bde meta/common-pc: Split out CPU and Drivers config fragments
   5f55e40 meta/common-pc: Cleanup common-pc.cfg and common-pc-gfx.cfg
   0a3f784 meta/common-pc: Add common Wifi drivers
   f4b9f5e meta/common-pc: Add common Realtek and Atheros Ethernet drivers
   4d9d3eb meta/common-pc: Build Ethernet and Wifi drivers as modules
   13141ee meta/common-pc: Refactor Ethernet and Wifi options

These are in support of a new genericx86 multi-target BSP.

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>