docs: submit-checklist: remove all of "make namespacecheck"

After commit 7dfbea4c ("scripts: remove namespace.pl"),
scripts/namespace.pl has been removed from the kernel, and "make
namespacecheck" has been removed from the English version of
submit-checklist.rst, so also remove it in the related translations.

Link: https://lkml.kernel.org/r/20231219125008.23007-6-yangtiezhu@loongson.cn


Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>