iwlwifi: disambiguate invalid DMA index warnings

The exact same error message is used in three different functions in
iwlagn. Add the function name to the error string to disambiguate where
the error is coming from.

Signed-off-by: Daniel Halperin <dhalperi@cs.washington.edu>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-tx.c b/drivers/net/wireless/iwlwifi/iwl-tx.c
index 686e176..1084fe0 100644
--- a/drivers/net/wireless/iwlwifi/iwl-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-tx.c
@@ -753,9 +753,9 @@
 	int nfreed = 0;
 
 	if ((idx >= q->n_bd) || (iwl_queue_used(q, idx) == 0)) {
-		IWL_ERR(priv, "Read index for DMA queue txq id (%d), index %d, "
-			  "is out of range [0-%d] %d %d.\n", txq_id,
-			  idx, q->n_bd, q->write_ptr, q->read_ptr);
+		IWL_ERR(priv, "%s: Read index for DMA queue txq id (%d), "
+			  "index %d is out of range [0-%d] %d %d.\n", __func__,
+			  txq_id, idx, q->n_bd, q->write_ptr, q->read_ptr);
 		return;
 	}