Bluetooth: Remove unused value strings.

Remove bluetooth_type_vals and bluetooth_direction_vals.

Change-Id: I2d39a59fc815f06d1a5cd5ab838e2bde37597469
Reviewed-on: https://code.wireshark.org/review/5842
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Reviewed-by: Michal Labedzki <michal.labedzki@tieto.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>