periph_common: call rtt_init from common init
periph_common: call rtt_init from common init

cladmi/RIOT,OlegHahm/RIOT,OlegHahm/RIOT,biboc/RIOT,lazytech-org/RIOT,avmelnikoff/RIOT,kYc0o/RIOT,smlng/RIOT,kYc0o/RIOT,ant9000/RIOT,gebart/RIOT,mtausig/RIOT,jasonatran/RIOT,yogo1212/RIOT,OTAkeys/RIOT,mtausig/RIOT,toonst/RIOT,biboc/RIOT,OTAkeys/RIOT,mfrey/RIOT,yogo1212/RIOT,ant9000/RIOT,miri64/RIOT,miri64/RIOT,basilfx/RIOT,authmillenon/RIOT,gebart/RIOT,miri64/RIOT,aeneby/RIOT,gebart/RIOT,A-Paul/RIOT,OTAkeys/RIOT,rfuentess/RIOT,yogo1212/RIOT,mtausig/RIOT,smlng/RIOT,A-Paul/RIOT,aeneby/RIOT,kaspar030/RIOT,yogo1212/RIOT,mfrey/RIOT,OlegHahm/RIOT,lazytech-org/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,mtausig/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,x3ro/RIOT,basilfx/RIOT,basilfx/RIOT,x3ro/RIOT,smlng/RIOT,authmillenon/RIOT,basilfx/RIOT,RIOT-OS/RIOT,ant9000/RIOT,BytesGalore/RIOT,kYc0o/RIOT,rfuentess/RIOT,josephnoir/RIOT,gebart/RIOT,aeneby/RIOT,biboc/RIOT,kYc0o/RIOT,OTAkeys/RIOT,smlng/RIOT,toonst/RIOT,rfuentess/RIOT,kbumsik/RIOT,mfrey/RIOT,josephnoir/RIOT,gebart/RIOT,RIOT-OS/RIOT,kbumsik/RIOT,cladmi/RIOT,BytesGalore/RIOT,BytesGalore/RIOT,cladmi/RIOT,toonst/RIOT,A-Paul/RIOT,BytesGalore/RIOT,rfuentess/RIOT,lazytech-org/RIOT,OlegHahm/RIOT,authmillenon/RIOT,lazytech-org/RIOT,authmillenon/RIOT,kaspar030/RIOT,mfrey/RIOT,toonst/RIOT,avmelnikoff/RIOT,jasonatran/RIOT,jasonatran/RIOT,cladmi/RIOT,kbumsik/RIOT,OTAkeys/RIOT,A-Paul/RIOT,josephnoir/RIOT,mfrey/RIOT,kbumsik/RIOT,josephnoir/RIOT,yogo1212/RIOT,kbumsik/RIOT,biboc/RIOT,mtausig/RIOT,kaspar030/RIOT,aeneby/RIOT,basilfx/RIOT,aeneby/RIOT,authmillenon/RIOT,jasonatran/RIOT,biboc/RIOT,ant9000/RIOT,RIOT-OS/RIOT,miri64/RIOT,smlng/RIOT,miri64/RIOT,BytesGalore/RIOT,toonst/RIOT,yogo1212/RIOT,ant9000/RIOT,OlegHahm/RIOT,A-Paul/RIOT,x3ro/RIOT,authmillenon/RIOT,cladmi/RIOT,avmelnikoff/RIOT,avmelnikoff/RIOT,josephnoir/RIOT,lazytech-org/RIOT,rfuentess/RIOT,avmelnikoff/RIOT,jasonatran/RIOT,x3ro/RIOT,x3ro/RIOT,kaspar030/RIOT