Remove SIOCSIFMTU handling and misuse of if_mtu values for MRU

Since there's now no way to select maximum receive unit size the
hardware is programmed to accept frame sizes up to 9216 which is
now the maximum (down from 15.5K since this is supposed to work
in all advanced configurations and gives slightly better flow
control watermark ranges) and split all frames larger 2K into
multiple fragments (code was already there but wasn't enabled).

Tested on 82599 (SFP+) and X540 (10GBaseT).
With input from dlg@.

0 files changed, 0 insertions, 0 deletions