cpu/stm32_common: add clock config documentation
cpu/stm32_common: add clock config documentation

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