net: phy: micrel: Staticize ksz8873mll_read_status()

ksz8873mll_read_status() is used only in this file.
Fix the following sparse warning:

drivers/net/phy/micrel.c:147:5: warning: symbol 'ksz8873mll_read_status' was not declared. Should it be static?
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/micrel.c

@@ -144,7 +144,7 @@ static int ks8051_config_init(struct phy_device *phydev)
 #define KSZ8873MLL_GLOBAL_CONTROL_4	0x06
 #define KSZ8873MLL_GLOBAL_CONTROL_4_DUPLEX	(1 << 6)
 #define KSZ8873MLL_GLOBAL_CONTROL_4_SPEED	(1 << 4)
-int ksz8873mll_read_status(struct phy_device *phydev)
+static int ksz8873mll_read_status(struct phy_device *phydev)
 {
 	int regval;