sis190: new PHY support

Reported to work on the WinFast 761GXK8MB-RS motherboard.

Plain 10/100 Mbps.

Signed-off-by: Paul Gibbons <paul@pkami.e7even.com>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>