dm: Emit the arch_cpu_init_dm() even only before relocation

The original function was only called once, before relocation. The new
one is called again after relocation. This was not the intent of the
original call. Fix this by renaming and updating the calling logic.

With this, chromebook_link64 makes it through SPL.

Fixes: 7fe32b34 ("event: Convert arch_cpu_init_dm() to use events")
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>