CONFIG_MACH_VPAC270 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Voipac PXA270

modulename: vpac270.ko

and/or

pxa2xx_vpac270.ko

configname: CONFIG_MACH_VPAC270

Linux Kernel Configuration
└─>Intel PXA2xx/PXA3xx Implementations
└─>Voipac PXA270
In linux kernel since version 2.6.35 (release Date: 2010-08-01)  
PXA270 based Single Board Computer.

source code:
arch/arm/mach-pxa/vpac270.c

depends
CONFIG_ARCH_PXA