CONFIG_SOC_PNX833X is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_SOC_PNX833X (not configurable)

configname: CONFIG_SOC_PNX833X

Linux Kernel Configuration
└─>SOC_PNX833X
In linux kernel since version 2.6.28 (release Date: 2008-12-24)  

is selected by
CONFIG_SERIAL_PNX8XXX