stdio: constify "name" arg in public api

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/common/stdio.c b/common/stdio.c
index ab7c5ab..b20772c 100644
--- a/common/stdio.c
+++ b/common/stdio.c
@@ -105,7 +105,7 @@
 	return &(devs.list);
 }
 
-struct stdio_dev* stdio_get_by_name(char* name)
+struct stdio_dev* stdio_get_by_name(const char *name)
 {
 	struct list_head *pos;
 	struct stdio_dev *dev;
@@ -155,7 +155,7 @@
  * returns 0 if success, -1 if device is assigned and 1 if devname not found
  */
 #ifdef	CONFIG_SYS_STDIO_DEREGISTER
-int stdio_deregister(char *devname)
+int stdio_deregister(const char *devname)
 {
 	int l;
 	struct list_head *pos;