CONFIG_ARCH_SOCFPGA is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
Altera SOCFPGA family
configname: CONFIG_ARCH_SOCFPGA
ARM system type
└─>Altera SOCFPGA family
In linux kernel since version 3.1 (release Date: 2011-10-24)
This enables support for Altera SOCFPGA Cyclone V platform