1) Set OPMODE_TTM in the default tsti_opmode, so that nway_status doesn't
blow up and report the wrong media type when statically configured. (This
code is a hack.)
2) Do not set IFM_ACTIVE (i.e. ignore SIASTAT_LS*) when in auto-negotiation
mode and negotiation has not completed (per 21143 manual).
3) Do not clear auto-negotiation mode; otherwise the chip will not
renegotiate on a link failure.
With these changes, 10/100 selection is more stable, and auto-negotiation
comes up with the right status and detects link, but the link does not work
unless it's hardwired. More work is needed.