ath5k: set 5/10 MHz supported channels and fix duration

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath5k/pcu.c b/drivers/net/wireless/ath/ath5k/pcu.c
index 1f16b42..c60d36a 100644
--- a/drivers/net/wireless/ath/ath5k/pcu.c
+++ b/drivers/net/wireless/ath/ath5k/pcu.c
@@ -144,11 +144,13 @@
 		sifs = AR5K_INIT_SIFS_HALF_RATE;
 		preamble *= 2;
 		sym_time *= 2;
+		bitrate = DIV_ROUND_UP(bitrate, 2);
 		break;
 	case AR5K_BWMODE_5MHZ:
 		sifs = AR5K_INIT_SIFS_QUARTER_RATE;
 		preamble *= 4;
 		sym_time *= 4;
+		bitrate = DIV_ROUND_UP(bitrate, 4);
 		break;
 	default:
 		sifs = AR5K_INIT_SIFS_DEFAULT_BG;