sis900: fix sis900_set_mode call parameters.

Leftover of 57d6d456 ("sis900: stop
using net_device.{base_addr, irq} and convert to __iomem.").

It is needed for suspend / resume to work.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Tested-by: Jan Janssen <medhefgo@web.de>
Cc: Daniele Venzano <venza@brownhat.org>
Signed-off-by: David S. Miller <davem@davemloft.net>