dtb: amd: Add AMD XGBE device tree file

Add AMD XGBE device tree file, which is available in AMD Seattle RevB.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
diff --git a/MAINTAINERS b/MAINTAINERS
index e349a32..9547a68 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -685,6 +685,7 @@
 L:	netdev@vger.kernel.org
 S:	Supported
 F:	drivers/net/ethernet/amd/xgbe/
+F:	arch/arm64/boot/dts/amd/amd-seattle-xgbe*.dtsi
 
 AMS (Apple Motion Sensor) DRIVER
 M:	Michael Hanselmann <linux-kernel@hansmi.ch>