cpu/esp8266: Moved stdio_init before periph_init

[maribu]

Contribution description

Added a call to stdio_init() right before calling `periph_init().

• This guarantees that DEBUG() is available early in boot process
• Forgotten in cpu: Moved stdio_init() prior to periph_init() for ARM targets #11367, this fixes broken stdio

Testing procedure

Flash and run e.g. examples/default or examples/hello-world and see if stdio is working again

Issues/PRs references

Fixes bug introduced in #11367

[maribu]

@gschorcht, @benpicco: My ESP8266s and ESP32s are all at office, so this and #12224 are completely untested so far ;-)

[benpicco]

Hm, no matter where I stick this in in startup.c, I can't get stdin to work.

If I put it back into sys/newlib_syscalls_default/syscalls.c:_init(), it's working, but not when even placing it right next to

    #ifdef MODULE_NEWLIB_SYSCALLS_DEFAULT
    _init();
    #endif

in cpu/esp8266/startup.c:ets_run()

[maribu]

@benpicco: Please test again.

[benpicco]

I think I see double.
I'll ponder why all the init functions are there twice at another time, now this is working again.

Tested on esp8266-esp-12x.

[maribu]

Thanks for testing and nothing the bug, and the bug in the bugfix :-D

[gschorcht]

I think I see double.
I'll ponder why all the init functions are there twice at another time, now this is working again.

Tested on esp8266-esp-12x.

There are two different startup functions for ESP8266, one if bare metal implementation without the terrible Espressif SDK is used used and one if the Espressif SDK is used (#if MODULE_ESP_SDK ... #else ... #endif). Since the Espressif SDK for ESP8266 is a horror it should be used only if it is really required, e.g., when the WiFi interface is used. Because the startup in both cases differs a lot, there is no common init function.