lan78xx: Don't reset the interface on open

Commit 92571a1a ("lan78xx: Connect phy early") moves the PHY
initialisation into lan78xx_probe, but lan78xx_open subsequently calls
lan78xx_reset. As well as forcing a second round of link negotiation,
this reset frequently prevents the phy interrupt from being generated
(even though the link is up), rendering the interface unusable.

Fix this issue by removing the lan78xx_reset call from lan78xx_open.

Fixes: 92571a1a

 ("lan78xx: Connect phy early")
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: David S. Miller <davem@davemloft.net>