sky2: Avoid allocating memory in sky2_resume

Allocating memory can fail, and since we have the memory we need
in sky2_resume when sky2_suspend is called, just stop the hardware
without freeing the memory it's using.

This avoids the possibility of failing because we can't allocate
memory in sky2_resume(), and allows sharing code with sky2_restart().

Signed-off-by: Mike McCormack <mikem@ring3k.org>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>