aspeed: Support for ast2500 Eval Board

ast2500 Eval Board device tree and board specific configuration.
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-aspeed/ast2500/Kconfig b/arch/arm/mach-aspeed/ast2500/Kconfig
index 05cb27e..b815153 100644
--- a/arch/arm/mach-aspeed/ast2500/Kconfig
+++ b/arch/arm/mach-aspeed/ast2500/Kconfig
@@ -11,4 +11,6 @@
 	  4 Serial ports, 4 USB ports, VGA port, PCIe, SD card slot,
 	  20 pin JTAG, pinouts for 14 I2Cs, 3 SPIs and eSPI, 8 PWMs.
 
+source "board/aspeed/evb_ast2500/Kconfig"
+
 endif