aio: remove no longer needed preempt_disable()
aio: remove no longer needed preempt_disable()

Based on feedback from Jens Axboe on 263782c1c95bbddbb022dc092fd89a36bb8d5577,
clean up get/put_reqs_available() to remove the no longer needed preempt_disable()
and preempt_enable() pair.

Signed-off-by: Benjamin LaHaise <b05c66fa21e46731bb89a779db663748f3df8f6a@kvack.org>
Cc: Jens Axboe <cd8c6775e60d6f67a6984377324e5290df3d5358@kernel.dk>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs