The firmware is split over multiple packages all of which need to use the same
source revision. Also, the firmware is currently not formally versioned, so
at least use the date the firmware was released in the versions.
* Update to the latest git revision
* Use the license file recently added upstream rather than a local one
* Tidy up a few things in the recipe
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>