scripts: kernel-doc: Remove workaround for @param... syntax

Commit 43756e34 ("scripts/kernel-doc: Add support for named variable
macro arguments") improved how named variable macro arguments are
handled, and changed how they are documented in kerneldoc comments
from "@param...", to "@param", deprecating the old syntax.

All users of the old syntax have since been converted, so this commit
finally removes support for it.

The output of "make htmldocs" is the same with and without this commit.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20230129150435.1510400-1-j.neuschaefer@gmx.net


Signed-off-by: Jonathan Corbet <corbet@lwn.net>