mpc86xx: Move setup_bats into cpu_init_f

In order to later allow for a physical relocation of the
flash, setup_bats, which sets up the final BAT mapping
for the board, needs to happen *after* init_laws().
Otherwise, there will be no window programmed for the flash
at the new physical location at the point when we change
the mmu translation.

Signed-off-by: Becky Bruce <becky.bruce@freescale.com>