sched: deadline: Cleanup goto label in pick_earliest_pushable_dl_task

Commit 8b5e770e ("sched/deadline: Optimize pull_dl_task()")
added a goto label seems would be better written as a while
loop.

So replace the goto with a while loop, to make it easier to read.

Reported-by: Todd Kjos <tkjos@google.com>
Signed-off-by: John Stultz <jstultz@google.com>
Reviewed-and-tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/20241206000009.1226085-1-jstultz@google.com