CONFIG_SOC_IMX50 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_SOC_IMX50 (not configurable)

modulename: mach-imx50.ko

configname: CONFIG_SOC_IMX50

Linux Kernel Configuration
└─>Freescale i.MX support
└─>SOC_IMX50
In linux kernel since version 2.6.38 (release Date: 2011-03-14)