sched/deadline: Fix sparse static warnings
sched/deadline: Remove unused variables
sched/deadline: No need to check p if dl_se is valid
sched/core: Fix htmldocs warnings
Bad Decisions

This reverts commit 0fd71a546de867502f53ab51c8e99a68bbfedca3.

Signed-off-by: Jean Francis Dominique S. Mabalot <jfdsmabalot@redhat.com>