The `ARCH` init level was added to solve a specific problem, call init
code (SYS_INIT/devices) before `z_cstart` in the `intel_adsp` platform.
The documentation claims it runs before `z_cstart`, but this is only
true if the SoC/arch takes care of calling:
```c
z_sys_init_run_level(_SYS_INIT_LEVEL_ARCH);
```
Which is only true for `intel_adsp` nowadays. So in practice, we now
have a platform specific init level. This patch proposes to do things in
a slightly different way. First, level name is renamed to `EARLY`, to
emphasize it runs in the early stage of the boot process. Then, it is
handled by the Kernel (inside `z_cstart()` before calling
`arch_kernel_init()`). This means that any platform can now use this
level. For `intel_adsp`, there should be no changes, other than
`gcov_static_init()` will be called before (I assume this will allow to
obtain coverage for code called in EARLY?).
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
e42f58ec94