CONFIG_SGI_HAS_ZILOG is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_SGI_HAS_ZILOG (not configurable)

configname: CONFIG_SGI_HAS_ZILOG

Linux Kernel Configuration
└─>SGI_HAS_ZILOG
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
is selected by
CONFIG_SERIAL_IP22_ZILOG

is depended by
CONFIG_SGI_IP28