MFC: r215298, r215459, r215714, r215716

MFC: r215298, r215459, r215714, r215716

- Change these drivers to take advantage and use the generic IEEE 802.3
  annex 31B full duplex flow control as well as the IFM_1000_T master
  support committed in r215297 (merged to stable/8 in r215881). For
  atphy(4) and jmphy(4) this includes changing these PHY drivers to no
  longer unconditionally advertise support for flow control but only if
  the selected media has IFM_FLOW set (or MIIF_FORCEPAUSE is set).
- Rename {atphy,jmphy}_auto() to {atphy,jmphy}_setmedia() as these handle
  other media types as well.

Reviewed by:	yongari (plus additional testing)
Obtained from:	NetBSD (partially), OpenBSD (partially)

git-svn-id: svn://svn.freebsd.org/base/stable/8@215882 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f