Linux 6.0 compat: register_shrinker() now var-arg

The 6.0 kernel added a printf-style var-arg for args > 0 to the
register_shrinker function, in order to add names to shrinkers, in
commit e33c267ab70de4249d22d7eab1cc7d68a889bac2. This enables the
shrinkers to have friendly names exposed in /sys/kernel/debug/shrinker/.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes #13748