sched/deadline: Clear the defer params

sched/deadline: Clear the defer params

The defer params were not cleared in __dl_clear_params. Clear them.

Without this is some of my test cases are flaking and the DL timer is
not starting correctly AFAICS.

Fixes: a110a81c52a9 ("sched/deadline: Deferrable dl server")
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Tested-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/20260126100050.3854740-2-arighi@nvidia.com