sched/deadline,rt: Remove unused functions for !CONFIG_SMP

The need_pull_[rt|dl]_task() and pull_[rt|dl]_task() functions are not
used on a !CONFIG_SMP system. Remove them.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/20220302183433.333029-6-dietmar.eggemann@arm.com