ARM: exynos: Remove secondary startup initialization from smp_prepare_cpus

We are taking care of setting secondary cpu boot address in
exynos_boot_secondary just before sending ipi to secondary CPUs,
so we can safely remove this setting from smp_prepare_cpus.

Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>