mwifiex: CPU mips optimization with NO_PKT_PRIO_TID

If we go through the entire for loop in
mwifiex_wmm_get_highest_priolist_ptr() and don't find any packets,
set highest_queued_prio to NO_PKT_PRIO_TID (< LOW_PRIO_TID).

Signed-off-by: Marc Yang <yangyang@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/mwifiex/wmm.c b/drivers/net/wireless/mwifiex/wmm.c
index 784ad4c..91634da 100644
--- a/drivers/net/wireless/mwifiex/wmm.c
+++ b/drivers/net/wireless/mwifiex/wmm.c
@@ -946,6 +946,12 @@
 				} while (ptr != head);
 			}
 
+			/* No packet at any TID for this priv. Mark as such
+			 * to skip checking TIDs for this priv (until pkt is
+			 * added).
+			 */
+			atomic_set(hqp, NO_PKT_PRIO_TID);
+
 			/* Get next bss priority node */
 			bssprio_node = list_first_entry(&bssprio_node->list,
 						struct mwifiex_bss_prio_node,