clk: imx: scu: bypass cpu clock save and restore

CPU clock is managed by ATF. No need save and restore.

Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Reviewed-by: Abel Vesa <abel.vesa@nxp.com>
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>