3rdparty: Update to latest commit in blobs repository

Update to commit 9f68e20e (AMD KaveriPI: Add PI header files to support
binary AGESA release), which is the latest commit in the blobs
repository.

Change-Id: I3d643f7565700272c22b59ed764c3269801f4413
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: http://review.coreboot.org/7595
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>