Adobe Lightroom will only load GPX, Canon 6D only saves NMEA data.

GPSBabel can be used to convert the *.log from the camera to *.gpx.

Download the software then load the log file for the input setting the type to NMEA 0183 sentences.

Set the output file name and set the format to GPX XML. Click OK to generate the GPX which can now be loaded into Lightroom.