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

CONFIG_DEBUG_MSM_UART (not configurable)

configname: CONFIG_DEBUG_MSM_UART

Linux Kernel Configuration
└─>Kernel hacking
└─>DEBUG_MSM_UART
In linux kernel since version 3.13 (release Date: 2014-01-19)