default or selected kernelversion does not have config value CONFIG_PINCTRL_MT7988.
Result is shown for kernelversion 6.6.78

Mediatek MT7988 pin control

modulename: pinctrl-mt7988.ko

configname: CONFIG_PINCTRL_MT7988

Linux Kernel Configuration
└─>Device Drivers
└─>Pin controllers
└─>MediaTek pinctrl drivers
└─>Device Tree and Open Firmware support
└─>Mediatek MT7988 pin control
In linux kernel since version 6.6.78 (release Date: 2025-02-17)  
source code:
drivers/pinctrl/mediatek/pinctrl-mt7988.c

depends
CONFIG_OF
CONFIG_PINCTRL
CONFIG_ARM64 or CONFIG_COMPILE_TEST
CONFIG_ARCH_AIROHA or CONFIG_ARCH_MEDIATEK or CONFIG_COMPILE_TEST or CONFIG_RALINK