r8169: revert bogus BMCR reset

Added during bf793295



The current code requests a reset but prohibits autoneg, 1000 Mb/s,
100 Mb/s and full duplex. The 8168 does not like it at all.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>