cxgb4: mark symbols static where possible

We get 10 warnings when building kernel with W=1:
drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c:304:5: warning: no previous prototype for 'cxgb4_dcb_enabled' [-Wmissing-prototypes]
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:194:5: warning: no previous prototype for 'setup_sge_queues_uld' [-Wmissing-prototypes]
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:241:6: warning: no previous prototype for 'free_sge_queues_uld' [-Wmissing-prototypes]
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:268:5: warning: no previous prototype for 'cfg_queues_uld' [-Wmissing-prototypes]
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:344:6: warning: no previous prototype for 'free_queues_uld' [-Wmissing-prototypes]
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:353:5: warning: no previous prototype for 'request_msix_queue_irqs_uld' [-Wmissing-prototypes]
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:379:6: warning: no previous prototype for 'free_msix_queue_irqs_uld' [-Wmissing-prototypes]
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:393:6: warning: no previous prototype for 'name_msix_vecs_uld' [-Wmissing-prototypes]
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:433:6: warning: no previous prototype for 'enable_rx_uld' [-Wmissing-prototypes]
drivers/net/ethernet/chelsio/cxgb4/cxgb4_uld.c:442:6: warning: no previous prototype for 'quiesce_rx_uld' [-Wmissing-prototypes]

In fact, these functions are only used in the file in which they are
declared and don't need a declaration, but can be made static.
so this patch marks these functions with 'static'.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>