ARM: mxs: Remove unused variable warning

Shuffle the macros around a little to remove the following warning
when building for i.MX28:

arch/arm/cpu/arm926ejs/mxs/spl_boot.c:44:26: warning: ‘iomux_boot’ defined but not used [-Wunused-const-variable=]
 static const iomux_cfg_t iomux_boot[] = {
                          ^~~~~~~~~~

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Tom Rini <trini@konsulko.com>
Cc: Stefano Babic <sbabic@denx.de>
1 file changed