Revert "rculist: Describe variadic macro argument in a Sphinx-compatible way"

This reverts commit f452ee09.

The workaround became unnecessary with commit 43756e34


("scripts/kernel-doc: Add support for named variable macro arguments").

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>