Filesystem: Use ENOTTY for default ioctl() handler

This is in line with Linux and FreeBSD.

cpukit/libcsupport/include/rtems/libio.h

@@ -1009,7 +1009,7 @@ ssize_t rtems_filesystem_default_write(
 );
 
 /**
- * @retval -1 Always.  The errno is set to ENOTSUP.
+ * @retval -1 Always.  The errno is set to ENOTTY.
  *
  * @see rtems_filesystem_ioctl_t.
  */

cpukit/libfs/src/defaults/default_ioctl.c

@@ -26,5 +26,5 @@ int rtems_filesystem_default_ioctl(
   void            *buffer
 )
 {
-  rtems_set_errno_and_return_minus_one( ENOTSUP );
+  rtems_set_errno_and_return_minus_one( ENOTTY );
 }