CONFIG_MACH_MT8135 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

MediaTek MT8135 SoCs support

configname: CONFIG_MACH_MT8135

Linux Kernel Configuration
└─>MediaTek SoC Support
└─>MediaTek MT8135 SoCs support
In linux kernel since version 4 (release Date: 2015-04-12)  

is selected by
CONFIG_PINCTRL_MT8135