cxgb3: ring rx door bell less frequently

Ring free lists door bell less frequently,
specifically every quarter of the active FL
size.

Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/cxgb3/adapter.h b/drivers/net/cxgb3/adapter.h
index fbe1569..95dce48 100644
--- a/drivers/net/cxgb3/adapter.h
+++ b/drivers/net/cxgb3/adapter.h
@@ -91,6 +91,7 @@
 struct sge_fl {                     /* SGE per free-buffer list state */
 	unsigned int buf_size;      /* size of each Rx buffer */
 	unsigned int credits;       /* # of available Rx buffers */
+	unsigned int pend_cred;     /* new buffers since last FL DB ring */
 	unsigned int size;          /* capacity of free list */
 	unsigned int cidx;          /* consumer index */
 	unsigned int pidx;          /* producer index */