CONFIG_MACH_TS409 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

QNAP TS-409

modulename: ts409-setup.ko

configname: CONFIG_MACH_TS409

Linux Kernel Configuration
└─>Orion Implementations
└─>QNAP TS-409
In linux kernel since version 2.6.27 (release Date: 2008-10-09)  
Say 'Y' here if you want your kernel to support the
QNAP TS-409 platform.

source code:
/arch/arm/mach-orion5x/