drivers: net: Mark functions as static in stmmac_platform.c

This patch marks the function stmmac_pltfr_freeze() and
stmmac_pltfr_restore() in stmmac_platform.c as static because they are
not used outside this file.

Thus, it also removes the following warnings in
ethernet/stmicro/stmmac/stmmac_platform.c:

drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c:222:5: warning: no previous prototype for ‘stmmac_pltfr_freeze’ [-Wmissing-prototypes]
drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c:236:5: warning: no previous prototype for ‘stmmac_pltfr_restore’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c

@@ -219,7 +219,7 @@ static int stmmac_pltfr_resume(struct device *dev)
 	return stmmac_resume(ndev);
 }
 
-int stmmac_pltfr_freeze(struct device *dev)
+static int stmmac_pltfr_freeze(struct device *dev)
 {
 	int ret;
 	struct plat_stmmacenet_data *plat_dat = dev_get_platdata(dev);
@@ -233,7 +233,7 @@ int stmmac_pltfr_freeze(struct device *dev)
 	return ret;
 }
 
-int stmmac_pltfr_restore(struct device *dev)
+static int stmmac_pltfr_restore(struct device *dev)
 {
 	struct plat_stmmacenet_data *plat_dat = dev_get_platdata(dev);
 	struct net_device *ndev = dev_get_drvdata(dev);