rds: Reintroduce statistics counting

rds: Reintroduce statistics counting

In commit 7e3f2952eeb1 ("rds: don't let RDS shutdown a connection
while senders are present"), refilling the receive queue was removed
from rds_ib_recv(), along with the increment of
s_ib_rx_refill_from_thread.

Commit 73ce4317bf98 ("RDS: make sure we post recv buffers")
re-introduces filling the receive queue from rds_ib_recv(), but does
not add the statistics counter. rds_ib_recv() was later renamed to
rds_ib_recv_path().

This commit reintroduces the statistics counting of
s_ib_rx_refill_from_thread and s_ib_rx_refill_from_cq.

Signed-off-by: Håkon Bugge <[email protected]>
Reviewed-by: Knut Omang <[email protected]>
Reviewed-by: Wei Lin Guay <[email protected]>
Reviewed-by: Shamir Rabinovitch <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Signed-off-by: David S. Miller <[email protected]>