CAM: Remove return value from xpt_path_sbuf()

It is wrong to call sbuf_len() on third-party sbuf.  If that sbuf
has a drain function, it ends up in assertion.  But even would it
work, it would return not newly written length, but the full one.
Searching through the sources I don't see this value used.

sys/cam/cam_xpt.c

@@ -3743,19 +3743,18 @@ xpt_print(struct cam_path *path, const char *fmt, ...)
 	sbuf_delete(&sb);
 }
 
-int
+char *
 xpt_path_string(struct cam_path *path, char *str, size_t str_len)
 {
 	struct sbuf sb;
-	int len;
 
 	sbuf_new(&sb, str, str_len, 0);
-	len = xpt_path_sbuf(path, &sb);
+	xpt_path_sbuf(path, &sb);
 	sbuf_finish(&sb);
-	return (len);
+	return (str);
 }
 
-int
+void
 xpt_path_sbuf(struct cam_path *path, struct sbuf *sb)
 {
 
@@ -3786,8 +3785,6 @@ xpt_path_sbuf(struct cam_path *path, struct sbuf *sb)
 		else
 			sbuf_printf(sb, "X): ");
 	}
-
-	return(sbuf_len(sb));
 }
 
 path_id_t

sys/cam/cam_xpt.h

@@ -102,9 +102,9 @@ int			xpt_path_comp(struct cam_path *path1,
 				      struct cam_path *path2);
 int			xpt_path_comp_dev(struct cam_path *path,
 					  struct cam_ed *dev);
-int			xpt_path_string(struct cam_path *path, char *str,
+char *			xpt_path_string(struct cam_path *path, char *str,
 					size_t str_len);
-int			xpt_path_sbuf(struct cam_path *path, struct sbuf *sb);
+void			xpt_path_sbuf(struct cam_path *path, struct sbuf *sb);
 path_id_t		xpt_path_path_id(struct cam_path *path);
 target_id_t		xpt_path_target_id(struct cam_path *path);
 lun_id_t		xpt_path_lun_id(struct cam_path *path);