block: Adding ROW scheduling algorithm

This patch adds the implementation of a new scheduling algorithm - ROW.
The policy of this algorithm is to prioritize READ requests over WRITE
as much as possible without starving the WRITE requests.
The requests are kept in queues according to their priority. The dispatch
is done in a Round Robin manner with a different slice for each queue.
READ request queues get bigger dispatch quantum than the write requests.

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

(https://patchwork.kernel.org/patch/1862271 and modified for 3.0.x)
Merge branch 'android-3.0.69' into kernel-forward

* android-3.0.69:
  block: Adding ROW scheduling algorithm
arm: p4notepq-3g_00_defconfig: Make ROW I/O Scheduler the default