CONFIG_ISA is not available for thedefaultarchitecture x86.
Result is shown for architecture m32r

ISA support

modulename: isa.ko

configname: CONFIG_ISA

Linux/M32R Kernel Configuration
└─>Bus options (PCI, PCMCIA, EISA, MCA, ISA)
└─>ISA support
In linux kernel since version 2.6.12  
Find out whether you have ISA slots on your motherboard. ISA is the
name of a bus system, i.e. the way the CPU talks to the other stuff
inside your box. If you have ISA, say Y, otherwise N.