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

i.MX1 support

modulename: mach-imx1.ko

configname: CONFIG_SOC_IMX1

Linux Kernel Configuration
└─>Freescale i.MX family
└─>i.MX1 support
In linux kernel since version 2.6.36 (release Date: 2010-10-20)  
This enables support for Freescale i.MX1 processor

source code: