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

CONFIG_IMX_HAVE_PLATFORM_FLEXCAN (not configurable)

modulename: platform-flexcan.ko

configname: CONFIG_IMX_HAVE_PLATFORM_FLEXCAN

Linux Kernel Configuration
└─>IMX_HAVE_PLATFORM_FLEXCAN
In linux kernel since version 2.6.36 (release Date: 2010-10-20)  
source code:
arch/arm/mach-imx/devices/platform-flexcan.c