Upgrade libav from version 9.16 to 9.18. Remove unused var INC_PR and
backport patch to fix CVE-2014-9676.
(From OE-Core rev: 1cac4dea1dd4a335752539feefc72372fb78a41d)
Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
