CONFIG_SOC_MT7621 is not available for thedefaultarchitecture x86.
Result is shown for architecture mips
MT7621
modulename: mt7621.ko
configname: CONFIG_SOC_MT7621
Ralink SoC selection
└─>MT7621
In linux kernel since version 3.10 (release Date: 2013-06-30)
The MT7621 system-on-a-chip includes an 880 MHz MIPS1004Kc dual-core CPU,
a 5-port 10/100/1000 switch/PHY and one RGMII.
a 5-port 10/100/1000 switch/PHY and one RGMII.