IB/ipath: Fix probe failure path

The failure path in ipath_init_one() does not match the cleanup code
in ipath_remove_one() and appears to leave interrupts enabled in some
cases.  Change it to match.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Roland Dreier <rolandd@cisco.com>