gnrc/sock: fix fallthrough warning (#7403)
gnrc/sock: fix fallthrough warning (#7403)

* gnrc/sock: fix fallthrough warning

* gnrc/sock: added spaces around "Fall Through."

miri64/RIOT,gebart/RIOT,rfuentess/RIOT,smlng/RIOT,authmillenon/RIOT,yogo1212/RIOT,neiljay/RIOT,josephnoir/RIOT,beurdouche/RIOT,kaspar030/RIOT,biboc/RIOT,jasonatran/RIOT,cladmi/RIOT,OTAkeys/RIOT,adrianghc/RIOT,avmelnikoff/RIOT,neumodisch/RIOT,smlng/RIOT,thomaseichinger/RIOT,mtausig/RIOT,gebart/RIOT,kaspar030/RIOT,OTAkeys/RIOT,gebart/RIOT,adrianghc/RIOT,lazytech-org/RIOT,aeneby/RIOT,mtausig/RIOT,authmillenon/RIOT,kbumsik/RIOT,neumodisch/RIOT,beurdouche/RIOT,smlng/RIOT,thomaseichinger/RIOT,aeneby/RIOT,rfuentess/RIOT,ks156/RIOT,immesys/RiSyn,immesys/RiSyn,authmillenon/RIOT,A-Paul/RIOT,ant9000/RIOT,mfrey/RIOT,yogo1212/RIOT,lazytech-org/RIOT,jfischer-phytec-iot/RIOT,kbumsik/RIOT,adjih/RIOT,x3ro/RIOT,RIOT-OS/RIOT,ant9000/RIOT,yogo1212/RIOT,authmillenon/RIOT,thomaseichinger/RIOT,lazytech-org/RIOT,LudwigOrtmann/RIOT,neumodisch/RIOT,mtausig/RIOT,adjih/RIOT,aeneby/RIOT,josephnoir/RIOT,mtausig/RIOT,ant9000/RIOT,miri64/RIOT,rfuentess/RIOT,biboc/RIOT,adjih/RIOT,cladmi/RIOT,kYc0o/RIOT,kYc0o/RIOT,roberthartung/RIOT,Josar/RIOT,neumodisch/RIOT,neiljay/RIOT,x3ro/RIOT,cladmi/RIOT,roberthartung/RIOT,LudwigKnuepfer/RIOT,mfrey/RIOT,rfuentess/RIOT,A-Paul/RIOT,kerneltask/RIOT,beurdouche/RIOT,BytesGalore/RIOT,x3ro/RIOT,beurdouche/RIOT,kaspar030/RIOT,mfrey/RIOT,josephnoir/RIOT,OlegHahm/RIOT,lazytech-org/RIOT,plushvoxel/RIOT,jfischer-phytec-iot/RIOT,hamilton-mote/RIOT-OS,biboc/RIOT,hamilton-mote/RIOT-OS,neumodisch/RIOT,A-Paul/RIOT,mfrey/RIOT,A-Paul/RIOT,mtausig/RIOT,yogo1212/RIOT,beurdouche/RIOT,aeneby/RIOT,rfuentess/RIOT,plushvoxel/RIOT,Josar/RIOT,smlng/RIOT,ks156/RIOT,smlng/RIOT,jfischer-phytec-iot/RIOT,adjih/RIOT,x3ro/RIOT,neumodisch/RIOT,kerneltask/RIOT,Josar/RIOT,plushvoxel/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,immesys/RiSyn,x3ro/RIOT,toonst/RIOT,hamilton-mote/RIOT-OS,hamilton-mote/RIOT-OS,kYc0o/RIOT,biboc/RIOT,adrianghc/RIOT,hamilton-mote/RIOT-OS,ks156/RIOT,kaspar030/RIOT,kbumsik/RIOT,ant9000/RIOT,basilfx/RIOT,authmillenon/RIOT,avmelnikoff/RIOT,miri64/RIOT,gebart/RIOT,ant9000/RIOT,LudwigOrtmann/RIOT,LudwigOrtmann/RIOT,adjih/RIOT,OlegHahm/RIOT,LudwigKnuepfer/RIOT,kerneltask/RIOT,jfischer-phytec-iot/RIOT,plushvoxel/RIOT,LudwigKnuepfer/RIOT,kbumsik/RIOT,ks156/RIOT,avmelnikoff/RIOT,josephnoir/RIOT,roberthartung/RIOT,kYc0o/RIOT,kbumsik/RIOT,cladmi/RIOT,aeneby/RIOT,jasonatran/RIOT,mfrey/RIOT,thomaseichinger/RIOT,adrianghc/RIOT,jasonatran/RIOT,miri64/RIOT,kerneltask/RIOT,BytesGalore/RIOT,OTAkeys/RIOT,avmelnikoff/RIOT,LudwigKnuepfer/RIOT,kaspar030/RIOT,adrianghc/RIOT,LudwigOrtmann/RIOT,kYc0o/RIOT,toonst/RIOT,cladmi/RIOT,basilfx/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,basilfx/RIOT,miri64/RIOT,BytesGalore/RIOT,immesys/RiSyn,lazytech-org/RIOT,A-Paul/RIOT,toonst/RIOT,josephnoir/RIOT,LudwigOrtmann/RIOT,basilfx/RIOT,kerneltask/RIOT,OlegHahm/RIOT,yogo1212/RIOT,roberthartung/RIOT,jasonatran/RIOT,roberthartung/RIOT,toonst/RIOT,BytesGalore/RIOT,biboc/RIOT,RIOT-OS/RIOT,immesys/RiSyn,authmillenon/RIOT,neiljay/RIOT,OTAkeys/RIOT,LudwigKnuepfer/RIOT,plushvoxel/RIOT,OTAkeys/RIOT,ks156/RIOT,LudwigOrtmann/RIOT,yogo1212/RIOT,immesys/RiSyn,jasonatran/RIOT,gebart/RIOT,avmelnikoff/RIOT,BytesGalore/RIOT,RIOT-OS/RIOT,toonst/RIOT,Josar/RIOT,neiljay/RIOT,neiljay/RIOT,thomaseichinger/RIOT,Josar/RIOT,jfischer-phytec-iot/RIOT,basilfx/RIOT