skge: fix warning when CONFIG_PM is defined but not CONFIG_PM_SLEEP

drivers/net/ethernet/marvell/skge.c:4046: warning: ‘skge_suspend’ defined but not used
drivers/net/ethernet/marvell/skge.c:4071: warning: ‘skge_resume’ defined but not used

Signed-off-by: Daniel Halperin <dhalperi@cs.washington.edu>
Cc: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>