The ODROID target was meant for the ODROID-XU4, hence it is renamed accordingly, to better indicate that.
Furthermore, gcc 4.9 added support for `-mcpu=cortex-a15.cortex-a7` to optimise support for this ARM big.LITTLE chip: https://www.gnu.org/software/gcc/gcc-4.9/changes.html#arm
`-mcpu=cortex-a9` was used as compatible option, while the Samsung Exynos 5422 SoC of the ODROID-XU4 actually has 4x Cortex-A15 and 4x Cortex-A7 CPUs: https://wiki.odroid.com/odroid-xu4/odroid-xu4
Signed-off-by: MichaIng <micha@dietpi.com>