block: Applied following patches:
1.block: Add support for reinsert a dispatched req
  https://github.com/AndreiLux/Perseus-UNIVERSAL5410/commit/7e28d2c1655c59478f3c61e614a04f4178fd1ba0
  Add support for reinserting a dispatched request back to the scheduler's internal data structures.
  This capability is used by the device driver when it chooses to interrupt the current request transmission and execute another (more urgent) pending request. For example: interrupting long write in order to handle pending read. The device driver re-inserts the remaining write request back to the scheduler, to be rescheduled for transmission later on.
  Add API for verifying whether the current scheduler supports reinserting requests mechanism. If reinsert mechanism isn't supported by the scheduler, this code path will never be activated.

2.block: Add API for urgent request handling
  https://github.com/AndreiLux/Perseus-UNIVERSAL5410/commit/c0cb5d702c18a8c4f0c6a565e7766703fabcf961
  This patch add support in block & elevator layers for handling urgent requests. The decision if a request is urgent or not is taken by the scheduler. Urgent request notification is passed to the underlying block device driver (eMMC for example). Block device driver may decide to interrupt the currently running low priority request to serve the new urgent request. By doing so READ latency is greatly reduced in read&write collision scenarios.
  Note that if the current scheduler doesn't implement the urgent request mechanism, this code path is never activated.

3.block: urgent request: remove unnecessary urgent marking
  https://github.com/AndreiLux/Perseus-UNIVERSAL5410/commit/ad8b184c6d18a33a41ad084c3eacf2317470ca4b
  An urgent request is marked by the scheduler in rq->cmd_flags with the REQ_URGENT flag. There is no need to add an additional marking by the block layer.

4.block: blk-core: add printk_ratelimit
  https://github.com/AndreiLux/Perseus-UNIVERSAL5410/commit/2a8c839fb4190d65f0dca04f7e630f2804400bea
  On failure of requests the console is flooded with prints, which result in a watchdog bark.
  This patch limits the number of prints to console thus, avoiding the bark.

5.block: urgent request: Update dispatch_urgent in case of requeue/reinsert
  https://github.com/AndreiLux/Perseus-UNIVERSAL5410/commit/9398bbd02439edbee3cf47bb159fa95269073a68
  The block layer implements a mechanism for verifying that the device driver won't be notified of an URGENT request if there is already an URGENT request in flight. This is due to the fact that interrupting an URGENT request isn't efficient.
  This patch fixes the above described mechanism in case the URGENT request was returned back to the block layer from some reason: by requeue or reinsert.

6.block: Remove "requeuing urgent req" error messages
  https://github.com/AndreiLux/Perseus-UNIVERSAL5410/commit/fa709c01d23bcb5afe4651bca751327b5f4e22f0
  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.

7.block: Remove some WARNON. Part of this patch.
  https://github.com/AndreiLux/Perseus-UNIVERSAL5410/commit/91ab76debc19a1fe5290369c4b4886dbb54ecbbc