arm: berlin: remove non-necessary flush_cache_all()

I believe the flush_cache_all() after scu_enable() is to "Ensure that
the data accessed by CPU0 before the SCU was initialised is visible
to the other CPUs." as commented in scu_enable(). So here
flush_cache_all() is a duplication, remove it.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>