commit f61bf8e7 upstream.

This fixes userspace code that builds on other architectures but fails
on xtensa due to references to structures that other architectures don't
refer to. E.g. this fixes the following issue with python-2.7.8:

  python-2.7.8/Modules/termios.c:861:25: error: invalid application
     of 'sizeof' to incomplete type 'struct serial_multiport_struct'
     {"TIOCSERGETMULTI", TIOCSERGETMULTI},
  python-2.7.8/Modules/termios.c:870:25: error: invalid application
     of 'sizeof' to incomplete type 'struct serial_multiport_struct'
     {"TIOCSERSETMULTI", TIOCSERSETMULTI},
  python-2.7.8/Modules/termios.c:900:24: error: invalid application
     of 'sizeof' to incomplete type 'struct tty_struct'
     {"TIOCTTYGSTRUCT", TIOCTTYGSTRUCT},
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
[lizf: Backported to 3.4: adjust filename]
Signed-off-by: Zefan Li <lizefan@huawei.com>