shared/hfp: Remove redundant check
shared/hfp: Remove redundant check

To make this check strcmp is good enough. No need to check len first
and then do memory compare.

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