cpu/esp8266: move most rodata sections to IROM
cpu/esp8266: move most rodata sections to IROM

Usually, all .rodata sections are placed in RAM by the Espressif SDK since IROM (flash) access requires 32-bit word aligned reads. thanks to the LoadStoreError exception handler from esp-open-rtos which is used now in RIOT-OS, it is also possible to place .rodata sections in IROM (flash) to save RAM resources.

ant9000/RIOT,smlng/RIOT,lazytech-org/RIOT,aeneby/RIOT,cladmi/RIOT,miri64/RIOT,x3ro/RIOT,yogo1212/RIOT,kaspar030/RIOT,x3ro/RIOT,OTAkeys/RIOT,mfrey/RIOT,mfrey/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,josephnoir/RIOT,ant9000/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,toonst/RIOT,cladmi/RIOT,mfrey/RIOT,toonst/RIOT,x3ro/RIOT,kaspar030/RIOT,OlegHahm/RIOT,smlng/RIOT,toonst/RIOT,authmillenon/RIOT,lazytech-org/RIOT,toonst/RIOT,ant9000/RIOT,kYc0o/RIOT,lazytech-org/RIOT,lazytech-org/RIOT,miri64/RIOT,smlng/RIOT,rfuentess/RIOT,authmillenon/RIOT,toonst/RIOT,basilfx/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,yogo1212/RIOT,aeneby/RIOT,yogo1212/RIOT,mtausig/RIOT,kYc0o/RIOT,jasonatran/RIOT,OTAkeys/RIOT,rfuentess/RIOT,aeneby/RIOT,mtausig/RIOT,OlegHahm/RIOT,mtausig/RIOT,OlegHahm/RIOT,cladmi/RIOT,miri64/RIOT,cladmi/RIOT,josephnoir/RIOT,rfuentess/RIOT,RIOT-OS/RIOT,miri64/RIOT,RIOT-OS/RIOT,mtausig/RIOT,kaspar030/RIOT,jasonatran/RIOT,mfrey/RIOT,OTAkeys/RIOT,kYc0o/RIOT,jasonatran/RIOT,jasonatran/RIOT,yogo1212/RIOT,authmillenon/RIOT,lazytech-org/RIOT,cladmi/RIOT,basilfx/RIOT,josephnoir/RIOT,OlegHahm/RIOT,x3ro/RIOT,smlng/RIOT,OTAkeys/RIOT,yogo1212/RIOT,mtausig/RIOT,rfuentess/RIOT,rfuentess/RIOT,ant9000/RIOT,josephnoir/RIOT,basilfx/RIOT,kYc0o/RIOT,aeneby/RIOT,yogo1212/RIOT,authmillenon/RIOT,josephnoir/RIOT,basilfx/RIOT,OTAkeys/RIOT,kaspar030/RIOT,miri64/RIOT,authmillenon/RIOT,smlng/RIOT,aeneby/RIOT,ant9000/RIOT,x3ro/RIOT,jasonatran/RIOT,authmillenon/RIOT,basilfx/RIOT,mfrey/RIOT