htb: remove printing of a deprecated overhead value

htb: remove printing of a deprecated overhead value

Remove printing according to the previously used encoding of mpu and
overhead values within the tc_ratespec's mpu field. This encoding is
no longer being used as a separate 'overhead' field in the ratespec
structure has been introduced.

Signed-off-by: Dmitrii Shcherbakov <fw.dmitrii@yandex.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Phil Sutter <phil@nwl.cc>