wireless: Introduce defines for BAR TID_INFO & MULTI_TID fields

While at it also fix the indention of the other IEEE80211_BAR_CTRL_ defines.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index b7075f3..018108d 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -128,7 +128,7 @@
 	memcpy(bar->ta, sdata->vif.addr, ETH_ALEN);
 	bar_control |= (u16)IEEE80211_BAR_CTRL_ACK_POLICY_NORMAL;
 	bar_control |= (u16)IEEE80211_BAR_CTRL_CBMTID_COMPRESSED_BA;
-	bar_control |= (u16)(tid << 12);
+	bar_control |= (u16)(tid << IEEE80211_BAR_CTRL_TID_INFO_SHIFT);
 	bar->control = cpu_to_le16(bar_control);
 	bar->start_seq_num = cpu_to_le16(ssn);