ARM: EXYNOS: call scu_enable() only in case of cortex-A9 processor

This patch reads the cpuid part number and if it matches with
cortex-A9, calls scu_enable()

Signed-off-by: Leela Krishna Amudala <l.krishna@samsung.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>