clk: rockchip: add 1.464GHz cpu-clock rate to rk3228

Add missing 1.464GHz clock rate to rk3228_cpuclk_rates[], which gets
referenced in the operating points but wasn't defined till now.

Signed-off-by: Justin Swartz <justin.swartz@risingedge.co.za>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>