Staging: sxg: fix napi interface build

Fix staging/sxg napi interface calls:

drivers/staging/sxg/sxg.c:1271: error: implicit declaration of function 'netif_rx_schedule_prep'
linux-next-20090209/drivers/staging/sxg/sxg.c:1272: error: implicit declaration of function '__netif_rx_schedule'
drivers/staging/sxg/sxg.c:1325: error: implicit declaration of function 'netif_rx_complete'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Mithlesh Thukral <mithlesh@linsyssoft.com>
Cc: LinSysSoft Sahara Team <saharaproj@linsyssoft.com>
Cc: Christopher Harrer <charrer@alacritech.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>