CONFIG_AVNET5282 is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k

Avnet 5282 board support

configname: CONFIG_AVNET5282

Linux Kernel Configuration
└─>Avnet 5282 board support
In linux kernel since version 2.6.18 (release Date: 2006-09-19)  
Support for the Avnet 5282 board.

selects
CONFIG_AVNET

depends
CONFIG_M528x