mips: xilfpga: Add device tree files

Mostly the same as the Kernel upstream device tree file except for

- alias for the serial console node
- ethernet node as the ethernet stuff isn't upstream on kernel.org yet
- uart clock-frequency passed directly in the node

Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/arch/mips/dts/Makefile b/arch/mips/dts/Makefile
index 2f04d73..5f311d4 100644
--- a/arch/mips/dts/Makefile
+++ b/arch/mips/dts/Makefile
@@ -6,6 +6,7 @@
 dtb-$(CONFIG_TARGET_AP143) += ap143.dtb
 dtb-$(CONFIG_TARGET_MALTA) += mti,malta.dtb
 dtb-$(CONFIG_TARGET_PIC32MZDASK) += pic32mzda_sk.dtb
+dtb-$(CONFIG_TARGET_XILFPGA) += nexys4ddr.dtb
 dtb-$(CONFIG_BOARD_TPLINK_WDR4300) += tplink_wdr4300.dtb
 
 targets += $(dtb-y)