vyos-kernel: enable atheros USB drivers in the helium 3.13 kernel

The current kernel (3.13) used in the helium branch of VyOS doesn't
include the carl9170 kernel modules (for atheros USB devices),
preventing the use of these cards on such a system.  The current
hydrogen release has support for these cards, but the required
firmware is also missing from this release.  See the additional
patch to the linux-firmware module that adds this.

http://wireless.kernel.org/en/users/Drivers/carl9170

Bug #267 http://bugzilla.vyos.net/show_bug.cgi?id=267

Firmware

Bug #268 http://bugzilla.vyos.net/show_bug.cgi?id=268