ALSA: Add const prefix to proc helper functions

Add appropriate const prefix to char * arguments in proc helper functions.
Also fixed the caller side to be proper const pointers.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/info.h

@@ -110,13 +110,13 @@ void snd_card_info_read_oss(struct snd_info_buffer *buffer);
 static inline void snd_card_info_read_oss(struct snd_info_buffer *buffer) {}
 #endif
 
-int snd_iprintf(struct snd_info_buffer *buffer, char *fmt, ...) \
+int snd_iprintf(struct snd_info_buffer *buffer, const char *fmt, ...) \
 				__attribute__ ((format (printf, 2, 3)));
 int snd_info_init(void);
 int snd_info_done(void);
 
 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len);
-char *snd_info_get_str(char *dest, char *src, int len);
+const char *snd_info_get_str(char *dest, const char *src, int len);
 struct snd_info_entry *snd_info_create_module_entry(struct module *module,
 					       const char *name,
 					       struct snd_info_entry *parent);

sound/core/info.c

@@ -108,7 +108,7 @@ static int resize_info_buffer(struct snd_info_buffer *buffer,
  *
  * Returns the size of output string.
  */
-int snd_iprintf(struct snd_info_buffer *buffer, char *fmt,...)
+int snd_iprintf(struct snd_info_buffer *buffer, const char *fmt, ...)
 {
 	va_list args;
 	int len, res;
@@ -727,7 +727,7 @@ EXPORT_SYMBOL(snd_info_get_line);
  * Returns the updated pointer of the original string so that
  * it can be used for the next call.
  */
-char *snd_info_get_str(char *dest, char *src, int len)
+const char *snd_info_get_str(char *dest, const char *src, int len)
 {
 	int c;
 

sound/core/oss/mixer_oss.c

@@ -1154,7 +1154,8 @@ static void snd_mixer_oss_proc_write(struct snd_info_entry *entry,
 				     struct snd_info_buffer *buffer)
 {
 	struct snd_mixer_oss *mixer = entry->private_data;
-	char line[128], str[32], idxstr[16], *cptr;
+	char line[128], str[32], idxstr[16];
+	const char *cptr;
 	int ch, idx;
 	struct snd_mixer_oss_assign_table *tbl;
 	struct slot *slot;

sound/core/oss/pcm_oss.c

@@ -2836,7 +2836,8 @@ static void snd_pcm_oss_proc_write(struct snd_info_entry *entry,
 				   struct snd_info_buffer *buffer)
 {
 	struct snd_pcm_str *pstr = entry->private_data;
-	char line[128], str[32], task_name[32], *ptr;
+	char line[128], str[32], task_name[32];
+	const char *ptr;
 	int idx1;
 	struct snd_pcm_oss_setup *setup, *setup1, template;