b43: use kernel api to replace b43 specific helper function

Use ieee80211_channel_to_frequency() to replace b43_channel_to_freq_{2,5}ghz(),
and remove unused b43_freq_to_channel_{2,5}ghz().

Signed-off-by: ZHAO Gang <gamerh2o@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/b43/xmit.c b/drivers/net/wireless/b43/xmit.c
index 50e5ddb..218a0f3 100644
--- a/drivers/net/wireless/b43/xmit.c
+++ b/drivers/net/wireless/b43/xmit.c
@@ -806,7 +806,8 @@
 		B43_WARN_ON(1);
 		/* FIXME: We don't really know which value the "chanid" contains.
 		 *        So the following assignment might be wrong. */
-		status.freq = b43_channel_to_freq_5ghz(chanid);
+		status.freq =
+			ieee80211_channel_to_frequency(chanid, status.band);
 		break;
 	case B43_PHYTYPE_G:
 		status.band = IEEE80211_BAND_2GHZ;
@@ -819,13 +820,12 @@
 	case B43_PHYTYPE_HT:
 		/* chanid is the SHM channel cookie. Which is the plain
 		 * channel number in b43. */
-		if (chanstat & B43_RX_CHAN_5GHZ) {
+		if (chanstat & B43_RX_CHAN_5GHZ)
 			status.band = IEEE80211_BAND_5GHZ;
-			status.freq = b43_channel_to_freq_5ghz(chanid);
-		} else {
+		else
 			status.band = IEEE80211_BAND_2GHZ;
-			status.freq = b43_channel_to_freq_2ghz(chanid);
-		}
+		status.freq =
+			ieee80211_channel_to_frequency(chanid, status.band);
 		break;
 	default:
 		B43_WARN_ON(1);