rt2x00: Add watchdog functions for HW queue

Add watchdog functions for managing the Queues inside the hardware.
Normally the driver doesn't have much to do with these queues
directly, but the Ralink drivers did implement watchdog functions
for these. These watchdog functions are not triggered that often,
compared to the other watchdog functions, but I have at least
seen them trigger once or twice during a long stresstest run.

v2: Add extra documentation for register fields

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2800.h b/drivers/net/wireless/rt2x00/rt2800.h
index c2cc126..002224c 100644
--- a/drivers/net/wireless/rt2x00/rt2800.h
+++ b/drivers/net/wireless/rt2x00/rt2800.h
@@ -412,10 +412,22 @@
 #define BCN_OFFSET1_BCN7		FIELD32(0xff000000)
 
 /*
- * PBF registers
- * Most are for debug. Driver doesn't touch PBF register.
+ * TXRXQ_PCNT: PBF register
+ * PCNT_TX0Q: Page count for TX hardware queue 0
+ * PCNT_TX1Q: Page count for TX hardware queue 1
+ * PCNT_TX2Q: Page count for TX hardware queue 2
+ * PCNT_RX0Q: Page count for RX hardware queue
  */
 #define TXRXQ_PCNT			0x0438
+#define TXRXQ_PCNT_TX0Q			FIELD32(0x000000ff)
+#define TXRXQ_PCNT_TX1Q			FIELD32(0x0000ff00)
+#define TXRXQ_PCNT_TX2Q			FIELD32(0x00ff0000)
+#define TXRXQ_PCNT_RX0Q			FIELD32(0xff000000)
+
+/*
+ * PBF register
+ * Debug. Driver doesn't touch PBF register.
+ */
 #define PBF_DBG				0x043c
 
 /*