r8169: remove unneeded check from rtl_link_chg_patch

r8169: remove unneeded check from rtl_link_chg_patch

rtl_link_chg_patch() can be called from rtl_open() to rtl8169_close()
only. And in rtl8169_close() phy_stop() ensures that this function
isn't called afterwards. So we don't need this check.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>