drivers/saul: Fixed documentation
drivers/saul: Fixed documentation

There is no need to distinguish between sensors for electrical power or other
types of power.

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