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

SPEAr300 Boards
└─>SPEAr300 Evaluation Board
In linux kernel since version 2.6.35 (release Date: 2010-08-01)  
Supports ST SPEAr300 Evaluation Board

source code:
arch/arm/mach-spear3xx/spear300_evb.c

depends
 or CONFIG_ARCH_SPEAR3XX