uboot-phytec

arm: rmobile: koelsch: Change to maximum CPU frequency

Maximum CPU clock of R8A7791 that are used in koelsch board is 1.5GHz.
This change to use the maximum clock in this board.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>