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

Palm T|X

modulename: palmtx.ko

and/or

pxa2xx_palmtx.ko

configname: CONFIG_MACH_PALMTX

Linux Kernel Configuration
└─>PXA2xx/PXA3xx-based
└─>Intel PXA2xx/PXA3xx Implementations
└─>Palm T|X
In linux kernel since version 2.6.27 (release Date: 2008-10-09)  
Say Y here if you intend to run this kernel on a Palm T|X
handheld computer.

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