net: stmmac: overwrite the dma_cap.addr64 according to HW design

net: stmmac: overwrite the dma_cap.addr64 according to HW design

The current IP register MAC_HW_Feature1[ADDR64] only defines
32/40/64 bit width, but some SOCs support others like i.MX8MP
support 34 bits but it maps to 40 bits width in MAC_HW_Feature1[ADDR64].
So overwrite dma_cap.addr64 according to HW real design.

Fixes: 94abdad6974a ("net: ethernet: dwmac: add ethernet glue logic for NXP imx8 chip")
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>