net: macb: Add DMA 64-bit address support for macb

net: macb: Add DMA 64-bit address support for macb

Enable 32-bit or 64-bit DMA in the macb driver based on the macb
hardware compatibility and it is configured with structure macb_config
in the driver.

The Microchip PolarFire SoC Memory Protection Unit(MPU) gives the 64-bit
DMA access with the GEM, the MPU transactions on the AXI bus is 64-bit
not 32-bit So 64-bit DMA is enabled for the Microchip PolarFire SoC GEM.

Signed-off-by: Padmarao Begari <padmarao.begari@microchip.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Bin Meng <bin.meng@windriver.com>