CONFIG_GNSS_SERIAL (not configurable)

modulename: gnss-serial.ko

configname: CONFIG_GNSS_SERIAL

Linux Kernel Configuration
└─>Device Drivers
└─>GNSS receiver support
└─>GNSS_SERIAL
In linux kernel since version 4.2 (release Date: 2015-08-30)  
source code:
drivers/gnss/
depends
CONFIG_GNSS

is depended by
CONFIG_GNSS_UBX_SERIAL