IB/mthca: Don't use privileged UAR for kernel access

Make kernel use UAR2 instead of UAR1 for hardware access: this adds
sanity checking from the hardware side, without any performance cost.
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mthca/mthca_uar.c

@@ -60,7 +60,7 @@ int mthca_init_uar_table(struct mthca_dev *dev)
 	ret = mthca_alloc_init(&dev->uar_table.alloc,
 			       dev->limits.num_uars,
 			       dev->limits.num_uars - 1,
-			       dev->limits.reserved_uars);
+			       dev->limits.reserved_uars + 1);
 	if (ret)
 		return ret;