[PATCH] drivers/net/wireless/libertas/fw.c: fix use-before-check

NULL checks should be performed before the dereference.

Spotted by the Coverity checker.
Signed-off-by: Eugene Teo <eteo@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/libertas/fw.c

@@ -333,18 +333,22 @@ static void command_timer_fn(unsigned long data)
 	unsigned long flags;
 
 	ptempnode = adapter->cur_cmd;
+	if (ptempnode == NULL) {
+		lbs_pr_debug(1, "PTempnode Empty\n");
+		return;
+	}
+
 	cmd = (struct cmd_ds_command *)ptempnode->bufvirtualaddr;
+	if (!cmd) {
+		lbs_pr_debug(1, "cmd is NULL\n");
+		return;
+	}
 
 	lbs_pr_info("command_timer_fn fired (%x)\n", cmd->command);
 
 	if (!adapter->fw_ready)
 		return;
 
-	if (ptempnode == NULL) {
-		lbs_pr_debug(1, "PTempnode Empty\n");
-		return;
-	}
-
 	spin_lock_irqsave(&adapter->driver_lock, flags);
 	adapter->cur_cmd = NULL;
 	spin_unlock_irqrestore(&adapter->driver_lock, flags);