CONFIG_M68K is not available for thedefaultarchitecture x86.
Result is shown for architecture m68knommu

CONFIG_M68K (not configurable)

configname: CONFIG_M68K

uClinux/68k (w/o MMU) Kernel Configuration
└─>M68K
In linux kernel since version 2.6.12  
selects
CONFIG_HAVE_IDE

is selected by
CONFIG_SND_SOC_WM9713