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/arch/powerpc/cpu/mpc8xx/fec.c b/arch/powerpc/cpu/mpc8xx/fec.c
index 754f8db..d4abeb1 100644
--- a/arch/powerpc/cpu/mpc8xx/fec.c
+++ b/arch/powerpc/cpu/mpc8xx/fec.c
@@ -63,9 +63,9 @@
 static int mii_discover_phy(struct eth_device *dev);
 #endif
 
-int fec8xx_miiphy_read(char *devname, unsigned char addr,
+int fec8xx_miiphy_read(const char *devname, unsigned char addr,
 		unsigned char  reg, unsigned short *value);
-int fec8xx_miiphy_write(char *devname, unsigned char  addr,
+int fec8xx_miiphy_write(const char *devname, unsigned char  addr,
 		unsigned char  reg, unsigned short value);
 
 static struct ether_fcc_info_s
@@ -990,7 +990,7 @@
  *	  Otherwise they hang in mii_send() !!! Sorry!
  *****************************************************************************/
 
-int fec8xx_miiphy_read(char *devname, unsigned char addr,
+int fec8xx_miiphy_read(const char *devname, unsigned char addr,
 		unsigned char  reg, unsigned short *value)
 {
 	short rdreg;    /* register working value */
@@ -1007,7 +1007,7 @@
 	return 0;
 }
 
-int fec8xx_miiphy_write(char *devname, unsigned char  addr,
+int fec8xx_miiphy_write(const char *devname, unsigned char  addr,
 		unsigned char  reg, unsigned short value)
 {
 	short rdreg;    /* register working value */