default or selected kernelversion does not have config value CONFIG_NET_VENDOR_MEDIATEK_STAGING.
Result is shown for kernelversion 6.7-rc3

MediaTek ethernet driver - staging version

configname: CONFIG_NET_VENDOR_MEDIATEK_STAGING

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>MediaTek ethernet driver - staging version
In linux kernel since version 4.2 (release Date: 2015-08-30)  
If you have an MT7621 Mediatek SoC with ethernet, say Y.