fdtput: Remove star from value_len documentation

When clang checks the documentation tags (with -Wdocumentation flag), it
reports the following warning:

    fdtput.c:70:11: error: parameter '*value_len' not found in the
    function declaration [-Werror,-Wdocumentation]
     * @param *value_len    Returns length of value encoded
              ^~~~~~~~~~
    fdtput.c:70:11: note: did you mean 'value_len'?
     * @param *value_len    Returns length of value encoded
              ^~~~~~~~~~
              value_len

As this sounds reasonable, remove the star from the documentation tag.

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

fdtput.c

@@ -67,7 +67,7 @@ static void report_error(const char *name, int namelen, int err)
  * @param arg		List of arguments from command line
  * @param arg_count	Number of arguments (may be 0)
  * @param valuep	Returns buffer containing value
- * @param *value_len	Returns length of value encoded
+ * @param value_len	Returns length of value encoded
  */
 static int encode_value(struct display_info *disp, char **arg, int arg_count,
 			char **valuep, int *value_len)