CONFIG_COMMON_CLK_AT91 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_COMMON_CLK_AT91 (not configurable)

configname: CONFIG_COMMON_CLK_AT91

Linux Kernel Configuration
└─>AT91/Microchip SoCs
└─>COMMON_CLK_AT91
In linux kernel since version 3.10 (release Date: 2013-06-30)