boards/stm32: add 54MHz and 108MHz divtable entries
boards/stm32: add 54MHz and 108MHz divtable entries

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