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 <[e-mail]>
Signed-off-by: Roland Dreier <[e-mail]>

drivers/infiniband/hw/mthca/mthca_uar.c

···
 	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;