[PATCH] sbp2: fix check of return value of hpsb_allocate_and_register_addrspace

[PATCH] sbp2: fix check of return value of hpsb_allocate_and_register_addrspace

I added a failure check in patch "sbp2: variable status FIFO address
(fix login timeout)" --- alas for a wrong error value.  This is a bug
since Linux 2.6.16.  Leads to NULL pointer dereference if the call
failed, and bogus failure handling if call succeeded.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>