bnxt_en: assign CPU affinity hints to bnxt_en IRQs

This patch provides hints to irqbalance to map bnxt_en device IRQs
to specific CPU cores. cpumask_local_spread() is used, which first
maps IRQs to near NUMA cores; when those cores are exhausted, IRQs
are mapped to far NUMA cores.

Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>