CONFIG_ARCH_DAVINCI644x is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

DaVinci 644x based system

configname: CONFIG_ARCH_DAVINCI644x

Linux Kernel Configuration
└─>TI DaVinci Implementations
└─>DaVinci 644x based system
In linux kernel since version 2.6.22 (release Date: 2007-07-08)