kernel-parameters.txt: fix pointers to sound parameters

The alsa parameters file was renamed to alsa-configuration.rst.

With regards to OSS, it got retired as a hole by  at changeset
727dede0ba8a ("sound: Retire OSS"). So, it doesn't make sense
to keep mentioning it at kernel-parameters.txt.

Fixes: 727dede0ba8a ("sound: Retire OSS")
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>