CONFIG_BOARD_SPEAR300_EVB is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

SPEAr300 Evaluation Board

modulename: spear300_evb.ko

configname: CONFIG_BOARD_SPEAR300_EVB

Linux Kernel Configuration
└─>SPEAr3xx Implementations
└─>SPEAr300 Evaluation Board
In linux kernel since version 2.6.35 (release Date: 2010-08-01)  
Supports ST SPEAr300 Evaluation Board

source code: