Remove macros that hide access to struct ifnet fields.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272179 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Add ipheth(4) to the hardware notes.

MFC after:	6 days


git-svn-id: svn+ssh://svn.freebsd.org/base/head@272180 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f