sfc: set and clear interrupt affinity hints

Use cpumask_local_spread to provide interrupt affinity hints
for each queue. This will spread interrupts across NUMA local
CPUs first, extending to remote nodes if needed.

Signed-off-by: Bert Kenward <bkenward@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>