sys/auto_init: Fixed initialization of sht1x
sys/auto_init: Fixed initialization of sht1x

 - the driver for sht1x is initialized two times
 - the second initialization is done only when SAUL is used, but sht1x needs
   to be initialized in any case. (SAUL registration is also done there, but
   only when SAUL is actually being used.)

This commit fixes both.

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