Add core pll node (core_clk) to manage cpu frequency.
core_clk represents pll itself.
input_clk represents clock signal source (basically xtal) which
comes to pll input.
Signed-off-by: NEugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>