scripts: sphinx-pre-install: Fix ctex support on Debian

The name of the package with ctexhook.sty is different on
Debian/Ubuntu.

Reported-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Tested-by: Akira Yokosawa <akiyks@gmail.com>
Link: https://lore.kernel.org/r/63882425609a2820fac78f5e94620abeb7ed5f6f.1641429634.git.mchehab@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>