clk: rockchip: remove mux_core_reg from rockchip_cpuclk_reg_data

mux_core_reg isn't been used anywhere, let's remove it.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

drivers/clk/rockchip/clk.h

@@ -245,7 +245,6 @@ struct rockchip_cpuclk_reg_data {
 	int		core_reg;
 	u8		div_core_shift;
 	u32		div_core_mask;
-	int		mux_core_reg;
 	u8		mux_core_alt;
 	u8		mux_core_main;
 	u8		mux_core_shift;