docs: kernel_abi.py: fix UTF-8 support

The parser breaks with UTF-8 characters with Sphinx 1.4.

Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/9e7c8e3b0efaa1ae0536da6493ab438bd3f9fe58.1604042072.git.mchehab+huawei@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>