toolchain/gcc: update 4.7-linaro to 2013.03

Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36154 3c298f89-4303-0410-b956-a3cf2f4a3e73
toolchain/gcc: add support for GCC 4.8.0

Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36155 3c298f89-4303-0410-b956-a3cf2f4a3e73
toolchain/gcc: remove reference to llvm introduced in r36155

Signed-off-by: Florian Fainelli <florian@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36156 3c298f89-4303-0410-b956-a3cf2f4a3e73