sky2: fix LED management

Fix problems in LED management, so ethtool -p works correctly on Yukon-EC
and other chips. The driver was incorrectly setting the PHY LED overide bits.
Moral: read the spec sheet, not the vendor driver.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>