mach-imx: Build imx6q-nitrogen6x.dtb
mach-imx: add ARCH_MX6 symbol

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
mach-imx: i.MX6Q: add FLEXCAN if CAN enabled

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
IMX_V6_V7: select ARCH_MX6 by default
add nitrogen6x_defconfig