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

Avila

configname: CONFIG_ARCH_AVILA

Linux Kernel Configuration
└─>Intel IXP4xx Implementation Options
└─>Avila
In linux kernel since version 2.6.12  
Say 'Y' here if you want your kernel to support the Gateworks
Avila Network Platform. For more information on this platform,
see Documentation/arm/IXP4xx.

selects
CONFIG_PCI