staging: lustre: obdclass: fix checking for obd_init_checks()

The obd_init_checks() function can either return -EOVERFLOW or -EINVAL
but we accidentally ignore -EINVAL returns.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>