arm: fsl: Adjust ordering of #ifndef CONFIG_SPL_BUILD
The secure boot header files incorrectly define SPL options only if
CONFIG_SPL_BUILD is defined. This means that the options are only enabled
in an SPL build, and not with a normal 'make xxx_defconfig'. This means
that moveconfig.py cannot work, since it sees the options as disabled even
when they may be manually enabled in an SPL build.