[toolchain/gcc]: upgrade Linaro gcc 4.8 to 4.8-2013.08

Signed-off-by: Imre Kaloz <kaloz@openwrt.org>



git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37945 3c298f89-4303-0410-b956-a3cf2f4a3e73