rtl8180: add rtl8187se fields to TX descriptor

This patch modifies the TX descriptor struct so it can work also
for rtl8187se.
Some reserved field is now meaningful, and where needed union is
used.
Signed-off-by: NAndrea Merello <andrea.merello@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtl818x/rtl8180/rtl8180.h

@@ -34,13 +34,25 @@ struct rtl8180_tx_desc {
 	__le16 rts_duration;
 	__le16 plcp_len;
 	__le32 tx_buf;
-	__le32 frame_len;
+	union{
+		__le32 frame_len;
+		struct {
+			__le16 frame_len_se;
+			__le16 frame_duration;
+		} __packed;
+	} __packed;
 	__le32 next_tx_desc;
 	u8 cw;
 	u8 retry_limit;
 	u8 agc;
 	u8 flags2;
-	u32 reserved[2];
+	/* rsvd for 8180/8185.
+	 * valid for 8187se but we dont use it
+	 */
+	u32 reserved;
+	/* all rsvd for 8180/8185 */
+	__le16 flags3;
+	__le16 frag_qsize;
 } __packed;
 
 struct rtl8180_rx_desc {