ath5k: fix some comment typos

Fix comment about dma sizes, brackets were missing. Replace 'insure' with
'ensure'.
Signed-off-by: NBruno Randolf <br1@einfach.org>
Acked-by: NBob Copeland <me@bobcopeland.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/ath5k.h

@@ -566,7 +566,7 @@ enum ath5k_pkt_type {
 )
 
 /*
- * DMA size definitions (2^n+2)
+ * DMA size definitions (2^(n+2))
  */
 enum ath5k_dmasize {
 	AR5K_DMASIZE_4B	= 0,

drivers/net/wireless/ath/ath5k/base.c

@@ -1230,13 +1230,13 @@ ath5k_rxbuf_setup(struct ath5k_softc *sc, struct ath5k_buf *bf)
 	 * not get overrun under high load (as can happen with a
 	 * 5212 when ANI processing enables PHY error frames).
 	 *
-	 * To insure the last descriptor is self-linked we create
+	 * To ensure the last descriptor is self-linked we create
 	 * each descriptor as self-linked and add it to the end.  As
 	 * each additional descriptor is added the previous self-linked
-	 * entry is ``fixed'' naturally.  This should be safe even
+	 * entry is "fixed" naturally.  This should be safe even
 	 * if DMA is happening.  When processing RX interrupts we
 	 * never remove/process the last, self-linked, entry on the
-	 * descriptor list.  This insures the hardware always has
+	 * descriptor list.  This ensures the hardware always has
 	 * someplace to write a new frame.
 	 */
 	ds = bf->desc;