fsl-layerscape: fix compile error with sec fw disabled

fsl-layerscape: fix compile error with sec fw disabled

If SEC FW support is not enabled (ARMV8_SEC_FIRMWARE_SUPPORT=n), below
compilation error appears
arch/arm/include/asm/arch-fsl-layerscape/fsl_icid.h:169:4: error:
'CONFIG_ARMV8_SEC_FIRMWARE_SUPPORT' undeclared here (not in a function)

Fix it by wrapping with CONFIG_IS_ENABLED().

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Reviewed-by: Horia Geanta <horia.geanta@nxp.com>
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>