cpu/esp32: fix of ctor and newlib initialization
cpu/esp32: fix of ctor and newlib initialization

Module `newlib` is now used by default. Therefore, the separation of initialization of ctors and the newlibc is not needed any longer. Instead of calling `do_global_ctors` and `_init` separately, `__libc_init_array` is called. Explicit function `do_global_ctors` is removed.
aeneby/RIOT,toonst/RIOT,miri64/RIOT,authmillenon/RIOT,smlng/RIOT,yogo1212/RIOT,authmillenon/RIOT,smlng/RIOT,josephnoir/RIOT,cladmi/RIOT,OTAkeys/RIOT,mtausig/RIOT,miri64/RIOT,josephnoir/RIOT,jasonatran/RIOT,yogo1212/RIOT,toonst/RIOT,toonst/RIOT,basilfx/RIOT,ant9000/RIOT,OTAkeys/RIOT,basilfx/RIOT,cladmi/RIOT,aeneby/RIOT,OlegHahm/RIOT,rfuentess/RIOT,ant9000/RIOT,x3ro/RIOT,miri64/RIOT,OTAkeys/RIOT,mtausig/RIOT,kYc0o/RIOT,mtausig/RIOT,authmillenon/RIOT,cladmi/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,ant9000/RIOT,miri64/RIOT,jasonatran/RIOT,yogo1212/RIOT,miri64/RIOT,x3ro/RIOT,x3ro/RIOT,rfuentess/RIOT,smlng/RIOT,aeneby/RIOT,ant9000/RIOT,aeneby/RIOT,OlegHahm/RIOT,OlegHahm/RIOT,x3ro/RIOT,kaspar030/RIOT,mtausig/RIOT,kaspar030/RIOT,aeneby/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,josephnoir/RIOT,basilfx/RIOT,kYc0o/RIOT,mtausig/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,kYc0o/RIOT,cladmi/RIOT,kaspar030/RIOT,yogo1212/RIOT,basilfx/RIOT,OlegHahm/RIOT,kYc0o/RIOT,smlng/RIOT,authmillenon/RIOT,authmillenon/RIOT,yogo1212/RIOT,jasonatran/RIOT,kaspar030/RIOT,toonst/RIOT,basilfx/RIOT,yogo1212/RIOT,RIOT-OS/RIOT,smlng/RIOT,cladmi/RIOT,toonst/RIOT,josephnoir/RIOT,x3ro/RIOT,kYc0o/RIOT,jasonatran/RIOT,ant9000/RIOT,rfuentess/RIOT,authmillenon/RIOT,josephnoir/RIOT,kaspar030/RIOT,rfuentess/RIOT,rfuentess/RIOT