rcar: CPG initial setting is done when SCP is started

CPG initial setting was done by TF-A when SCP was becoming active.
With this patch CPG initial setting is done by SCP.

Signed-off-by: Tsutomu Muroya <tsutomu.muroya.jy@bp.renesas.com>
Signed-off-by: Nicolas Royer <nroyer@baylibre.com>