CONFIG_MACH_STM32F469 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

STMicrolectronics STM32F469

configname: CONFIG_MACH_STM32F469

Linux Kernel Configuration
└─>STMicrolectronics STM32F469
In linux kernel since version 3.10 (release Date: 2013-06-30)  
selects

CONFIG_ARM_AMBA

depends
CONFIG_ARCH_STM32 |
| CONFIG_ARM_SINGLE_ARMV7M