CONFIG_SBC8560 is not available for thedefaultarchitecture x86.
Result is shown for architecture ppc

WindRiver PowerQUICC III SBC8560

modulename: sbc85xx.ko

configname: CONFIG_SBC8560

Machine Type
└─>WindRiver PowerQUICC III SBC8560
In linux kernel since version 2.6.12  
This option enables support for the WindRiver PowerQUICC III
SBC8560 board.

source code:
/arch/ppc/platforms/85xx/
is selected by
CONFIG_MTD_WRSBC8260