At present bootstage will try to read the timer very early after relocation.
When driver model is used to provide the timer, we cannot read it until
driver model is ready. Correct this by adding a separate stage for the
post-relocation bootstage init.

This fixes booting on chromebook_link.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Mugunthan V N <mugunthanvnm@ti.com>