block: Remove requeuing urgent req error messages [CAF]

It is possible for URGENT request to be requeued/reinserted if it was fetched during the creation of a packed list. This end case is rare and is not handled at the moment.

This patch changes the messages notifying of the above to debug level (instead of error) in order to clear the dmesg log.

Change-Id: Ie8bc067e61559a6f702077b95c5dbcc426404232
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>