w1: w1_ds28e04: unlock on error path in w1_f1C_write_pio()

We should unlock here before returning.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>