xtensa: ISS: fix call to split_if_spec

stable inclusion
from stable-v5.10.188
commit 81fb8a58d4ec10c489ee87b315bca5fbcbf155bc
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8KYFP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=81fb8a58d4ec10c489ee87b315bca5fbcbf155bc



--------------------------------

commit bc8d5916 upstream.

split_if_spec expects a NULL-pointer as an end marker for the argument
list, but tuntap_probe never supplied that terminating NULL. As a result
incorrectly formatted interface specification string may cause a crash
because of the random memory access. Fix that by adding NULL terminator
to the split_if_spec argument list.

Cc: stable@vger.kernel.org
Fixes: 7282bee7 ("[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 8")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>