From: "Michael S. Tsirkin" <mst@mellanox.co.il>

We don't need to write to the ECR to clear events when using MSI-X, since we
never read the ECR anyway.
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>