CONFIG_M68030 is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k

68030 support

configname: CONFIG_M68030

Linux/68k Kernel Configuration
└─>Platform dependent setup
└─>68030 support
In linux kernel since version 2.6.12  
If you anticipate running this kernel on a computer with a MC68030
processor, say Y. Otherwise, say N. Note that a MC68EC030 will not
work, as it does not include an MMU (Memory Management Unit).

depends
NOT CONFIG_MMU_SUN3

is depended by
CONFIG_SUN3X