[PATCH] it87: Fix oops on removal

Fix an oops on it87 module removal when no supported hardware was
found.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/hwmon/it87.c

@@ -1186,7 +1186,8 @@ static int __init sm_it87_init(void)
 
 static void __exit sm_it87_exit(void)
 {
-	i2c_isa_del_driver(&it87_isa_driver);
+	if (isa_address)
+		i2c_isa_del_driver(&it87_isa_driver);
 	i2c_del_driver(&it87_driver);
 }