rt2x00: Remove last usage of beacon_int from ieee80211_config

This removes the last usage of beacon_int inside the iee80211_config
structure from rt2x00. The attempt is a bit hackish, and subject to
change in the future when the entire rt2x00_dev structure is
cleaned up and restructured.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2500pci.c b/drivers/net/wireless/rt2x00/rt2500pci.c
index f95cb64..08b30d0 100644
--- a/drivers/net/wireless/rt2x00/rt2500pci.c
+++ b/drivers/net/wireless/rt2x00/rt2500pci.c
@@ -569,7 +569,7 @@
 	if (state == STATE_SLEEP) {
 		rt2x00pci_register_read(rt2x00dev, CSR20, &reg);
 		rt2x00_set_field32(&reg, CSR20_DELAY_AFTER_TBCN,
-				   (libconf->conf->beacon_int - 20) * 16);
+				   (rt2x00dev->beacon_int - 20) * 16);
 		rt2x00_set_field32(&reg, CSR20_TBCN_BEFORE_WAKEUP,
 				   libconf->conf->listen_interval - 1);