Link handling changes (Andy Lutomirski <luto@myrealbox.com>):
- removed rtl8169_hw_phy_reset() and its busy loop;
- RTL8169_PHY_TIMEOUT is x10 to account for the removal of the
  phy_link_down_cnt loop in rtl8169_phy_timer();
- added spinlocking in timer context for rtl8169_phy_timer to avoid
  messing with the {set/get}_settings commands issued via ethtool;
- more TBI stuff.

This patch differs from the former version on the following points:
- the LinkChg irq does not enable the phy timer when the link goes
  down any more;
- the phy timer is not enabled in rtl8169_set_speed();
- removal of the initial renegotiation hack.