ifmedia changes:

• Extend the number of available subtypes for Ethernet media by using some

of the ifmedia word's option bits to help denote subtypes. As a result, the
number of possible Ethernet subtype values increases from 31 to 511.

• Use some of those new values to define new media types.

• lacp_compose_key() recgonizes the new Ethernet media types added. (Change made as required by a comment in if_media.h)

• New ioctl, SIOGIFXMEDIA, to handle getting the new extended media types. SIOCGIFMEDIA is retained for backwards compatibility.

• Changes to ifconfig to allow it to handle the new extended media types.

Submitted by: mike@karels.net (original), hselasky
Reviewed by: jfvogel, gnn, hselasky
Approved by: jfvogel (mentor), gnn (mentor)
Differential Revision: http://reviews.freebsd.org/D1965