cpu/common/esp32: use 'awk/printf' instead of 'echo'
cpu/common/esp32: use 'awk/printf' instead of 'echo'

  - replaces 'echo -n' and 'awk' with 'printf' and 'awk'
  - replaces rest of 'echo' statements with printf

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