[IB] mthca: fix off by one in clr_int calculation

We should use the first word of the clear interrupt register if
the bit we're after is < 32, not < 31.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/mthca/mthca_eq.c b/drivers/infiniband/hw/mthca/mthca_eq.c
index 78152a8..c81fa8e 100644
--- a/drivers/infiniband/hw/mthca/mthca_eq.c
+++ b/drivers/infiniband/hw/mthca/mthca_eq.c
@@ -836,7 +836,7 @@
 		dev->eq_table.clr_mask =
 			swab32(1 << (dev->eq_table.inta_pin & 31));
 		dev->eq_table.clr_int  = dev->clr_base +
-			(dev->eq_table.inta_pin < 31 ? 4 : 0);
+			(dev->eq_table.inta_pin < 32 ? 4 : 0);
 	}
 
 	dev->eq_table.arm_mask = 0;