x86: mp_init: Set up the CPU numbers at the start

x86: mp_init: Set up the CPU numbers at the start

At present each CPU is given a number when it starts itself up. While this
saves a tiny amount of time by doing the device-tree read in parallel, it
is confusing that the numbering happens on the fly.

Move this code into mp_init() and do it at the start.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>