Adding Proprietary Link Speed to sys/net/if_media.h

[David Christensen]

> > I'm working on improving the fiber support for the bce 
> driver.  One of
> 
> Should be fine but you might want to post a patch to be concrete.
> 
> 	Sam

I'm just looking at adding a media type as follows:

#define IFM_2500_SX	21	/* 2500BaseSX - multi-mode fiber */

I've only briefly explored whether any other changes are necessary
anywhere outside of my driver.  If anyone has any thoughts on
where I should consider more changes I'd appreciate the feedback.

Dave