iser-target: Remove interrupt coalescing

It is disabled at the moment, we will get that back
in once the target is more stable.

This reverts commit 95b60f0
"Add support for completion interrupt coalescing"

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --cc drivers/infiniband/ulp/isert/ib_isert.c
Simple merge

diff --cc drivers/infiniband/ulp/isert/ib_isert.h
Simple merge