[PATCH] sky2: ethtool rx_coalesce settings fix

This fixes setting rx_coalesce_usecs_irq via ethtool in sky2.
The write was directed to the wrong register.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>