IB/ehca: Implement modify_port

Add "Modify Port" verb support to eHCA driver.  The IB communication
manager needs this to set the IsCM port capability bit when
initializing.

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/ehca/ehca_classes.h b/drivers/infiniband/hw/ehca/ehca_classes.h
index 82ded44..10fb8fb 100644
--- a/drivers/infiniband/hw/ehca/ehca_classes.h
+++ b/drivers/infiniband/hw/ehca/ehca_classes.h
@@ -106,6 +106,7 @@
 	struct ehca_mr *maxmr;
 	struct ehca_pd *pd;
 	struct h_galpas galpas;
+	struct mutex modify_mutex;
 };
 
 struct ehca_pd {