net: stmmac: set IRQ affinity hint for multi MSI vectors

Certain platform likes Intel mGBE has independent hardware IRQ resources
for TX and RX DMA operation. In preparation to support XDP TX, we add IRQ
affinity hint to group both RX and TX queue of the same queue ID to the
same CPU.

Changes in v2:
 - IRQ affinity hint need to set to null before IRQ is released.
   Thanks to issue reported by Song, Yoong Siang.

Reported-by: Song, Yoong Siang <yoong.siang.song@intel.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>