CONFIG_MACH_NOKIA_N800 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_MACH_NOKIA_N800 (not configurable)

configname: CONFIG_MACH_NOKIA_N800

Linux Kernel Configuration
└─>MACH_NOKIA_N800
In linux kernel since version 2.6.32 (release Date: 2009-12-02)  
depends
 or CONFIG_ARCH_OMAP2PLUS

is depended by
CONFIG_MACH_NOKIA_N8X0