prism54: Convert wpa_sem in a mutex

The semaphore wpa_sem is used as mutex, convert it to the mutex API

Signed-off-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Acked-by: Luis R. Rodriguez <mcgrof@winlab.rutgers.edu>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/prism54/islpci_dev.h b/drivers/net/wireless/prism54/islpci_dev.h
index 85ddf89..8e55a5f 100644
--- a/drivers/net/wireless/prism54/islpci_dev.h
+++ b/drivers/net/wireless/prism54/islpci_dev.h
@@ -178,7 +178,7 @@
 	int wpa; /* WPA mode enabled */
 	struct list_head bss_wpa_list;
 	int num_bss_wpa;
-	struct semaphore wpa_sem;
+	struct mutex wpa_lock;
 	u8 wpa_ie[MAX_WPA_IE_LEN];
 	size_t wpa_ie_len;