CONFIG_MAC_SCC is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k
default or selected kernelversion does not have config value CONFIG_MAC_SCC.
Result is shown for kernelversion 5.4.194

Macintosh serial support

configname: CONFIG_MAC_SCC

Linux/68k Kernel Configuration
└─>Character devices
└─>Macintosh serial support
In linux kernel since version 2.6.12  
depends
CONFIG_MAC