[openfabrics-ewg] IB/ipath - initialize diagpkt file on device init only

[Robert Walsh]

> Sigh.  Yeah.  Code go boom.  I'll roll it again.  We had been ignoring 
> the failure anyway before this patch.  I'll just make sure we do a 
> dev_warn and atomic_dec if ipath_cdev_init fails.

Scrub that - I'm going to roll all this into ipath_diag_add and make it 
all a bit simpler.  I'll send out a new patch tomorrow afternoon, after 
some testing.

Regards,
  Robert.