stmmac: fix sparse warnings

This patch fixes the following sparse warnings.

drivers/net/ethernet/stmicro/stmmac/enh_desc.c:381:30: warning: symbol 'enh_desc_ops' was not declared. Should it be static?
drivers/net/ethernet/stmicro/stmmac/norm_desc.c:253:30: warning: symbol 'ndesc_ops' was not declared. Should it be static?
drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c:141:33: warning: symbol 'stmmac_ptp' was not declared. Should it be static?

There is no functional change.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Giuseppe CAVALLARO <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/common.h

@@ -341,6 +341,9 @@ struct stmmac_desc_ops {
 	int (*get_rx_timestamp_status) (void *desc, u32 ats);
 };
 
+extern const struct stmmac_desc_ops enh_desc_ops;
+extern const struct stmmac_desc_ops ndesc_ops;
+
 struct stmmac_dma_ops {
 	/* DMA core initialization */
 	int (*init) (void __iomem *ioaddr, int pbl, int fb, int mb,
@@ -410,6 +413,8 @@ struct stmmac_hwtimestamp {
 	 u64(*get_systime) (void __iomem *ioaddr);
 };
 
+extern const struct stmmac_hwtimestamp stmmac_ptp;
+
 struct mac_link {
 	int port;
 	int duplex;

drivers/net/ethernet/stmicro/stmmac/stmmac.h

@@ -122,9 +122,7 @@ int stmmac_mdio_unregister(struct net_device *ndev);
 int stmmac_mdio_register(struct net_device *ndev);
 int stmmac_mdio_reset(struct mii_bus *mii);
 void stmmac_set_ethtool_ops(struct net_device *netdev);
-extern const struct stmmac_desc_ops enh_desc_ops;
-extern const struct stmmac_desc_ops ndesc_ops;
-extern const struct stmmac_hwtimestamp stmmac_ptp;
+
 int stmmac_ptp_register(struct stmmac_priv *priv);
 void stmmac_ptp_unregister(struct stmmac_priv *priv);
 int stmmac_resume(struct net_device *ndev);