CONFIG_APM_RTC_IS_GMT is not available for thedefaultarchitecture x86.
Result is shown for architecture i386
default or selected kernelversion does not have config value CONFIG_APM_RTC_IS_GMT.
Result is shown for kernelversion 5.4.123

RTC stores time in GMT


Linux Kernel Configuration
└─>Power management options (ACPI, APM)
└─>APM (Advanced Power Management) BIOS Support
└─>RTC stores time in GMT
In linux kernel since version 2.6.12  
Say Y here if your RTC (Real Time Clock a.k.a. hardware clock)
stores the time in GMT (Greenwich Mean Time). Say N if your RTC
stores localtime.

It is in fact recommended to store GMT in your RTC, because then you
don't have to worry about daylight savings time changes. The only
reason not to use GMT in your RTC is if you also run a broken OS
that doesn't understand GMT.