parport: fix freeing freed memory

After the reference count becomes 0 when put_device() is called, it will
execute the release callback where we are freeing all the allocated
memory associated with the device. So if we just continue on the error
path then we are again freeing devname and trying to dereference par_dev
which has already been free-ed in the release callback.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>