'Add support to build with linaro toolchain.
thanks to slimbean:
 Support complex toolchains

Instead of specifying the name of the toolchain and relying on arm-eabi-
use the entire path to the custom toolchain.

Add the following line to BoardConfig.mk to use the custom toolchain for kernel
For linaro:
TARGET_KERNEL_CUSTOM_TOOLCHAIN := linaro/bin/arm-linux-gnueabihf-

For GCC 4.4.3:
TARGET_KERNEL_CUSTOM_TOOLCHAIN := arm-eabi-4.4.3/bin/arm-eabi-'