shared/hfp: Don't update offset if string parsing failed
shared/hfp: Don't update offset if string parsing failed

mapfau/bluez,mapfau/bluez,pkarasev3/bluez,pkarasev3/bluez,silent-snowman/bluez,mapfau/bluez,ComputeCycles/bluez,pstglia/external-bluetooth-bluez,silent-snowman/bluez,ComputeCycles/bluez,pkarasev3/bluez,pstglia/external-bluetooth-bluez,pstglia/external-bluetooth-bluez,silent-snowman/bluez,pstglia/external-bluetooth-bluez,pkarasev3/bluez,mapfau/bluez,ComputeCycles/bluez,ComputeCycles/bluez,silent-snowman/bluez