target_cpu() should initially target all cpus, not just cpu 0.
Otherwise systems with lots of disks can exhaust the interrupt
vectors on cpu 0 if a large number of disks are discovered
before the irq balancer is running.

Note: UV code only...
Signed-off-by: Jack Steiner <steiner@sgi.com>
LKML-Reference: <20100311184328.GA21433@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>