CONFIG_MACH_DNS323 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

D-Link DNS-323

modulename: dns323-setup.ko

configname: CONFIG_MACH_DNS323

Linux Kernel Configuration
└─>Orion Implementations
└─>D-Link DNS-323
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
Say 'Y' here if you want your kernel to support the
D-Link DNS-323 platform.

source code:
arch/arm/mach-orion5x/dns323-setup.c