defconfig: 8084: Set ROW as the default block I/O scheduler

The ROW block I/O scheduler was developed with the mobile devices needs
in mind, where we favor user experience upon everything else, thus we
want to give READ I/O requests as much priority as possible.

The main idea of the ROW scheduling policy is to dispatch READ requests
with higher priority, while write starvation is considered.

The benefit of ROW block I/O scheduler is to improve the READ throughput
and latency in READ/WRITE collisions.
The READ latency worst case is improved both in sequential and random read
scenarios.

Change-Id: I5343c0f5d5a0848febc966d66b993525a01b3c4c
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>