In imx28evk_defconfig file, you can see that CONFIG_CAN_BCM, CONFIG_CAN_DEV and CONFIG_CAN_VCAN are disabled by default.
CONFIG_CAN=y
CONFIG_CAN_RAW=y
# CONFIG_CAN_BCM is not set
#
# CAN Device Drivers
#
# CONFIG_CAN_VCAN is not set
# CONFIG_CAN_DEV is not set
# CONFIG_CAN_DEBUG_DEVICES is not set
CONFIG_CAN_FLEXCAN=m
You can run ./ltib -m config , then choose configure kernel.
In kernel configure menu, Networking support -> Can bus subsystem support, to enable them.
Grace