kconfig: Propagate const

Commit 2e7a091 made struct file->name a const char*, but forgot to
constify all users of it.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/kconfig/kxgettext.c

@@ -63,11 +63,11 @@ static char *escape(const char* text, char *bf, int len)
 
 struct file_line {
 	struct file_line *next;
-	char*		 file;
-	int		 lineno;
+	const char *file;
+	int lineno;
 };
 
-static struct file_line *file_line__new(char *file, int lineno)
+static struct file_line *file_line__new(const char *file, int lineno)
 {
 	struct file_line *self = malloc(sizeof(*self));
 
@@ -90,7 +90,8 @@ struct message {
 
 static struct message *message__list;
 
-static struct message *message__new(const char *msg, char *option, char *file, int lineno)
+static struct message *message__new(const char *msg, char *option,
+				    const char *file, int lineno)
 {
 	struct message *self = malloc(sizeof(*self));
 
@@ -130,7 +131,8 @@ static struct message *mesage__find(const char *msg)
 	return m;
 }
 
-static int message__add_file_line(struct message *self, char *file, int lineno)
+static int message__add_file_line(struct message *self, const char *file,
+				  int lineno)
 {
 	int rc = -1;
 	struct file_line *fl = file_line__new(file, lineno);
@@ -145,7 +147,8 @@ static int message__add_file_line(struct message *self, char *file, int lineno)
 	return rc;
 }
 
-static int message__add(const char *msg, char *option, char *file, int lineno)
+static int message__add(const char *msg, char *option, const char *file,
+			int lineno)
 {
 	int rc = 0;
 	char bf[16384];