net: stmmac: build the dwmac-socfpga platform driver for Stratix10

The Stratix10 SoC is an AARCH64 based platform that shares the same ethernet
controller that is on other SoCFPGA platforms. Build the platform driver.

Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>