gcc: use a case statement to pick the correct arm9/cortex gcc linaro toolchain from version.sh

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>
gcc: for arm9 targets use gcc-arm-none-eabi-4_7-2013q1-20130313-linux.tar.bz2

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>