net: stmmac: Remove unneeded I/O read caught by cppcheck

Cppcheck found a case where a local variable was being assigned a value,
but not used. There seems to be no reason to read this register before
assigning a new value, so addressing thie issue.

cppcheck --force --enable=all --inline-suppr . shows ...

Variable 'value' is reassigned a value before the old one has been used.
Signed-off-by: NVince Bridgers <vbridgers2013@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c

@@ -320,11 +320,8 @@ static void dwmac1000_set_eee_timer(void __iomem *ioaddr, int ls, int tw)
 
 static void dwmac1000_ctrl_ane(void __iomem *ioaddr, bool restart)
 {
-	u32 value;
-
-	value = readl(ioaddr + GMAC_AN_CTRL);
 	/* auto negotiation enable and External Loopback enable */
-	value = GMAC_AN_CTRL_ANE | GMAC_AN_CTRL_ELE;
+	u32 value = GMAC_AN_CTRL_ANE | GMAC_AN_CTRL_ELE;
 
 	if (restart)
 		value |= GMAC_AN_CTRL_RAN;