iw_cxgb4: pass window scale in flowc work request

This will allow FW to not send more data to TP (which would then need to
be buffered). Pass the negotiated TCP window scale to FW in the FLOWC WR.

Also refactor send_flowc() a bit to clean it up.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/cxgb4/iw_cxgb4.h

@@ -910,7 +910,10 @@ enum conn_pre_alloc_buffers {
 	CN_MAX_CON_BUF
 };
 
-#define FLOWC_LEN 80
+enum {
+	FLOWC_LEN = offsetof(struct fw_flowc_wr, mnemval[FW_FLOWC_MNEM_MAX])
+};
+
 union cpl_wr_size {
 	struct cpl_abort_req abrt_req;
 	struct cpl_abort_rpl abrt_rpl;
@@ -977,6 +980,7 @@ struct c4iw_ep {
 	unsigned int retry_count;
 	int snd_win;
 	int rcv_win;
+	u32 snd_wscale;
 	struct c4iw_ep_stats stats;
 };