board_init_f for the am62a is missing the call to spl_enable_cache which
exists for all other am62 platforms (check am625_init.c &
am62p5_init.c).
This allows the usage of caches while loading and parsing the u-boot.img
FIT resulting in ~2x speedup in the A53 SPL stage.
Signed-off-by: Anshul Dalal <anshuld@ti.com>