CONFIG_SOC_IMX1 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_SOC_IMX1 (not configurable)

configname: CONFIG_SOC_IMX1

Linux Kernel Configuration
└─>SOC_IMX1
In linux kernel since version 2.6.36 (release Date: 2010-10-20)  

depends
CONFIG_ARCH_MX1