CONFIG_MCA is not available for the selected architecture x86.
Result is shown for architecture i386

MCA support

modulename: mca.ko

configname: CONFIG_MCA

Linux Kernel Configuration
└─>Bus options (PCI, PCMCIA, EISA, MCA, ISA)
└─>MCA support
In linux kernel since version 2.6.12 )
MicroChannel Architecture is found in some IBM PS/2 machines and
laptops. It is a bus system similar to PCI or ISA. See
<a href="https://www.kernel.org/doc/Documentation/mca.txt">Documentation/mca.txt</a> (and especially the web page given
there) before attempting to build an MCA bus kernel.