CONFIG_MACH_N30 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Acer N30 family

modulename: mach-n30.ko

configname: CONFIG_MACH_N30

Linux Kernel Configuration
└─>S3C2410 Machines
└─>Acer N30 family
In linux kernel since version 2.6.12  
Say Y here if you want suppt for the Acer N30, Acer N35,
Navman PiN570, Yakumo AlphaX or Airis NC05 PDAs.

source code:
arch/arm/mach-s3c2410/mach-n30.c