Avoid cluttering board file with CONFIG_SPL_BUILD ifdefs
by moving SPL related functions into separate file.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Tested-by: Pau Pajuelo <ppajuel@gmail.com>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>