ath5k: struct ath5k_desc cleanups

* make struct ath5k_desc clearer by directly including unions of structures,
  which correspond to the hardware descriptors of different HW versions (5210
  and 5212). before they were casted at onto ath5k_desc at different points
  (e.g.  ds_hw[2]).

* rename some structures and variable names to make their use clearer, e.g.
  struct ath5k_hw_4w_tx_desc to ath5k_hw_4w_tx_ctl.

* substitute "old" with "5210" and "new" with "5212" (eg. rename
  ath5k_hw_proc_new_rx_status() to ath5k_hw_proc_5212_rx_status()) because old
  and new are relative and we might have a newer structure at some point.

* unify structs ath5k_hw_old_rx_status and ath5k_hw_new_rx_status into one
  ath5k_hw_rx_status, because they only differ in the flags and masks.

drivers/net/wireless/ath5k/ath5k.h:     Changes-licensed-under: ISC
drivers/net/wireless/ath5k/debug.c:     Changes-licensed-under: GPL
drivers/net/wireless/ath5k/hw.c:        Changes-licensed-under: ISC
drivers/net/wireless/ath5k/hw.h:        Changes-licensed-under: ISC

Signed-off-by: Bruno Randolf <bruno@thinktube.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath5k/ath5k.h b/drivers/net/wireless/ath5k/ath5k.h
index 04efcee..2af7982 100644
--- a/drivers/net/wireless/ath5k/ath5k.h
+++ b/drivers/net/wireless/ath5k/ath5k.h
@@ -273,12 +273,13 @@
 #define SHPREAMBLE_FLAG(_ix) \
 	(HAS_SHPREAMBLE(_ix) ? AR5K_SET_SHORT_PREAMBLE : 0)
 
+
 /****************\
   TX DEFINITIONS
 \****************/
 
 /*
- * Tx Descriptor
+ * TX Status
  */
 struct ath5k_tx_status {
 	u16	ts_seqnum;
@@ -426,7 +427,7 @@
 \****************/
 
 /*
- * Rx Descriptor
+ * RX Status
  */
 struct ath5k_rx_status {
 	u16	rs_datalen;
@@ -457,8 +458,6 @@
 };
 
 
-
-
 /**************************\
  BEACON TIMERS DEFINITIONS
 \**************************/
@@ -500,20 +499,22 @@
 #define TSF_TO_TU(_tsf) (u32)((_tsf) >> 10)
 
 
-
 /********************\
   COMMON DEFINITIONS
 \********************/
 
 /*
- * Atheros descriptor
+ * Atheros hardware descriptor
  */
 struct ath5k_desc {
-	u32	ds_link;
-	u32	ds_data;
-	u32	ds_ctl0;
-	u32	ds_ctl1;
-	u32	ds_hw[4];
+	u32	ds_link;	/* physical address of the next descriptor */
+	u32	ds_data;	/* physical address of data buffer (skb) */
+
+	union {
+		struct ath5k_hw_5210_tx_desc	ds_tx5210;
+		struct ath5k_hw_5212_tx_desc	ds_tx5212;
+		struct ath5k_hw_all_rx_desc	ds_rx;
+	} ud;
 
 	union {
 		struct ath5k_rx_status rx;