IB/qib: Modify software pma counters to use percpu variables

The counters, unicast_xmit, unicast_rcv, multicast_xmit, multicast_rcv
are now maintained as percpu variables.

The mad code is modified to add a z_ latch so that the percpu counters
monotonically increase with appropriate adjustments in the reset,
read logic to maintain the z_ latch.

This patch also corrects the fact the unitcast_xmit wasn't handled
at all for UC and RC QPs.

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/qib/qib.h

@@ -1186,7 +1186,7 @@ int qib_setup_eagerbufs(struct qib_ctxtdata *);
 void qib_set_ctxtcnt(struct qib_devdata *);
 int qib_create_ctxts(struct qib_devdata *dd);
 struct qib_ctxtdata *qib_create_ctxtdata(struct qib_pportdata *, u32, int);
-void qib_init_pportdata(struct qib_pportdata *, struct qib_devdata *, u8, u8);
+int qib_init_pportdata(struct qib_pportdata *, struct qib_devdata *, u8, u8);
 void qib_free_ctxtdata(struct qib_devdata *, struct qib_ctxtdata *);
 
 u32 qib_kreceive(struct qib_ctxtdata *, u32 *, u32 *);