net/mlx5e: Eliminate build warnings on no previous prototype

Fix these gcc warnings on drivers/net/ethernet/mellanox/mlx5:

[..]/core/lib/clock.c:454:6: warning: no previous prototype for 'mlx5_init_clock' [-Wmissing-prototypes]
[..]/core/lib/clock.c:510:6: warning: no previous prototype for 'mlx5_cleanup_clock' [-Wmissing-prototypes]
[..]/core/en_main.c:3141:5: warning: no previous prototype for 'mlx5e_setup_tc' [-Wmissing-prototypes]
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

@@ -2994,7 +2994,7 @@ static int mlx5e_setup_tc_block(struct net_device *dev,
 }
 #endif
 
-int mlx5e_setup_tc(struct net_device *dev, enum tc_setup_type type,
+static int mlx5e_setup_tc(struct net_device *dev, enum tc_setup_type type,
 			  void *type_data)
 {
 	switch (type) {

drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c

@@ -34,6 +34,7 @@
 #include <linux/highmem.h>
 #include <rdma/mlx5-abi.h>
 #include "en.h"
+#include "clock.h"
 
 enum {
 	MLX5_CYCLES_SHIFT	= 23