miiphy: constify device name

The driver name does not need to be writable, so constify it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
diff --git a/drivers/net/at91_emac.c b/drivers/net/at91_emac.c
index 245da12..0912f52 100644
--- a/drivers/net/at91_emac.c
+++ b/drivers/net/at91_emac.c
@@ -170,7 +170,7 @@
 	return (at91_emac_t *) netdev->iobase;
 }
 
-int  at91emac_mii_read(char *devname, unsigned char addr,
+int  at91emac_mii_read(const char *devname, unsigned char addr,
 		unsigned char reg, unsigned short *value)
 {
 	at91_emac_t *emac;
@@ -181,7 +181,7 @@
 }
 
 
-int  at91emac_mii_write(char *devname, unsigned char addr,
+int  at91emac_mii_write(const char *devname, unsigned char addr,
 		unsigned char reg, unsigned short value)
 {
 	at91_emac_t *emac;