ANDROID: block: Restore request_queue.requeue_work

Restore the struct request_queue requeue_work member without modifying
the KMI. The approach of this patch works because blk_dev_init() is the
only function that needs to know the size of a request queue structure.

This patch prepares for reverting "Preserve the order of requeued
requests".

See also commit 619ba336 ("ANDROID: block: Remove
request_queue.requeue_work").

Bug: 298142254
Change-Id: I108ceb9f58cec521f81fd8cf82f38185376a7a6b
Signed-off-by: Bart Van Assche <bvanassche@google.com>