W1: ioremap balanced with iounmap

ioremap must be balanced with iounmap in error path.

Please consider for 2.6.19.

Signed-off-by: Amol Lad <amol@verismonetworks.com>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>