ps3_gelic_wireless: fix format warning

Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/ps3_gelic_wireless.c b/drivers/net/ps3_gelic_wireless.c
index d520e9e..448c5b6 100644
--- a/drivers/net/ps3_gelic_wireless.c
+++ b/drivers/net/ps3_gelic_wireless.c
@@ -1449,7 +1449,7 @@
 	void *buf = NULL;
 	size_t len;
 
-	pr_debug("%s: <- always=%d essid_len=%d\n", __func__,
+	pr_debug("%s: <- always=%d essid_len=%z\n", __func__,
 		 always_scan, essid_len);
 	if (mutex_lock_interruptible(&wl->scan_lock))
 		return -ERESTARTSYS;