Fix compile warnings for const correctness

Commit 6e37b1a3a25004d3df5867de49fff6b3fc9c4f04 modifies several net calls
to take a (const char *) parameter instead of (char *), but in some cases
the modified functions call other functions taking (char *).  The end result
is warnings about discarding the const qualifier.

This patch fixes these other function signatures.

Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
diff --git a/drivers/net/at91_emac.c b/drivers/net/at91_emac.c
index 0912f52..d82459b 100644
--- a/drivers/net/at91_emac.c
+++ b/drivers/net/at91_emac.c
@@ -162,7 +162,7 @@
 
 #if defined(CONFIG_MII) || defined(CONFIG_CMD_MII)
 
-at91_emac_t *get_emacbase_by_name(char *devname)
+at91_emac_t *get_emacbase_by_name(const char *devname)
 {
 	struct eth_device *netdev;
 
diff --git a/drivers/net/eepro100.c b/drivers/net/eepro100.c
index 5cb767a..22e14e3 100644
--- a/drivers/net/eepro100.c
+++ b/drivers/net/eepro100.c
@@ -321,7 +321,8 @@
 /* Check if given phyaddr is valid, i.e. there is a PHY connected.
  * Do this by checking model value field from ID2 register.
  */
-static struct eth_device* verify_phyaddr (char *devname, unsigned char addr)
+static struct eth_device* verify_phyaddr (const char *devname,
+						unsigned char addr)
 {
 	struct eth_device *dev;
 	unsigned short value;
diff --git a/drivers/net/phy/miiphybb.c b/drivers/net/phy/miiphybb.c
index 2768c75..1045cf1 100644
--- a/drivers/net/phy/miiphybb.c
+++ b/drivers/net/phy/miiphybb.c
@@ -143,7 +143,7 @@
 	}
 }
 
-static inline struct bb_miiphy_bus *bb_miiphy_getbus(char *devname)
+static inline struct bb_miiphy_bus *bb_miiphy_getbus(const char *devname)
 {
 #ifdef CONFIG_BITBANGMII_MULTI
 	int i;
@@ -246,7 +246,7 @@
  * Returns:
  *   0 on success
  */
-int bb_miiphy_read(char *devname, unsigned char addr,
+int bb_miiphy_read(const char *devname, unsigned char addr,
 		   unsigned char reg, unsigned short *value)
 {
 	short rdreg; /* register working value */
@@ -327,7 +327,7 @@
  * Returns:
  *   0 on success
  */
-int bb_miiphy_write (char *devname, unsigned char addr,
+int bb_miiphy_write (const char *devname, unsigned char addr,
 		     unsigned char reg, unsigned short value)
 {
 	struct bb_miiphy_bus *bus;