block: row: Remove warning massage from add_request

Regular priority queues is marked as "starved" if it skipped a dispatch
due to being empty. When a new request is added to a "starved" queue
it will be marked as urgent.
The removed WARN_ON was warning about an impossible case when a regular
priority (read) queue was marked as starved but wasn't empty. This is
a possible case due to the bellow:
If the device driver fetched a read request that is pending for
transmission and an URGENT request arrives, the fetched read will be
reinserted back to the scheduler. Its possible that the queue it will be
reinserted to was marked as "starved" in the meanwhile due to being empty.

CRs-fixed: 517800
Change-Id: Iaae642ea0ed9c817c41745b0e8ae2217cc684f0c
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
block: bfq: Squashed update from BFQ-v6r2 to BFQ-v7r1

Change-Id: I7498f1f60253b0631a0ce36e7c20d6ec4e1df8f5
block: bfq: Squashed update from BFQ-v7r1 to BFQ-v7r2

Change-Id: I90a2156ae874fed703aafa22b721f59a0db40c51