if_bge.c rev. 1.205, 1.209, 1.210

Summary:
In some situations we were not clearing pending link state attentions.
Because of this we were not getting further interrupts for link state
changes, thus never went into iface UP state and thus could not transmit.

The only way out of this was an incoming packet generating an rx interrupt
and making us call into bge_link_upd.

What we do now is force an interrupt at the end of bge_ifmedia_upd_locked
so we will call bge_link_upd, clear the link state attention and get
further interrupts.

While the initial version was not expected to work with all chips
the later update in rev. 1.210 is.