default or selected kernelversion does not have config value CONFIG_SUNXI_CCU_MUX.
Result is shown for kernelversion 6.4.14

CONFIG_SUNXI_CCU_MUX (not configurable)

modulename: ccu_mux.ko

configname: CONFIG_SUNXI_CCU_MUX

Linux Kernel Configuration
└─>Device Drivers
└─>Common Clock Framework
└─>SUNXI_CCU_MUX
In linux kernel since version 4.1 (release Date: 2015-06-21)  
source code:
drivers/clk/sunxi-ng/ccu_mux.c