ARM: exynos_defconfig: Enable SCHED_MC and ENERGY_MODEL

The Energy Model (EM) is needed to run Energy Aware Scheduler (EAS).
Enable ENERGY_MODEL to make that happen. This will increase energy
efficiency of the big.LITTLE platforms (e.g. Exynos5422) by smarter
decisions in scheduling tasks in non-heavy workloads.

Add SCHED_MC in order to create another level in scheduling domains: 'MC'.
This improves scheduler's decisions on platforms with CPU clusters, such
as big.LITTLE.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>