Prism54: Convert mgmt_sem to the mutex API

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
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 736666d..4e0182c 100644
--- a/drivers/net/wireless/prism54/islpci_dev.h
+++ b/drivers/net/wireless/prism54/islpci_dev.h
@@ -26,6 +26,7 @@
 #include <linux/wireless.h>
 #include <net/iw_handler.h>
 #include <linux/list.h>
+#include <linux/mutex.h>
 
 #include "isl_38xx.h"
 #include "isl_oid.h"
@@ -164,7 +165,7 @@
 	wait_queue_head_t reset_done;
 
 	/* used by islpci_mgt_transaction */
-	struct semaphore mgmt_sem; /* serialize access to mailbox and wqueue */
+	struct mutex mgmt_lock; /* serialize access to mailbox and wqueue */
 	struct islpci_mgmtframe *mgmt_received;	  /* mbox for incoming frame */
 	wait_queue_head_t mgmt_wqueue;            /* waitqueue for mbox */