default or selected kernelversion does not have config value CONFIG_SP7021_EMAC.
Result is shown for kernelversion 6.9-rc1

Sunplus Dual 10M/100M Ethernet devices

modulename: sp7021_emac.ko

configname: CONFIG_SP7021_EMAC

Linux Kernel Configuration
└─>Device Drivers
└─>Network device support
└─>Ethernet driver support
└─>Sunplus Dual 10M/100M Ethernet devices
In linux kernel since version 5.2 (release Date: 2019-07-07)  
If you have Sunplus dual 10M/100M Ethernet devices, say Y.
The network device creates two net-device interfaces.
To compile this driver as a module, choose M here. The
module will be called sp7021_emac.

source code: