aspeed: Add Aspeed G6/eval configuration

Add base configuration metadata for the Aspeed AST2600 and its
evaluation board.

Initially point at the Aspeed SDK until kernel and u-boot support is
added upstream.

Change-Id: I13b6b64ccc011fb5ab2d68ed5a383a81811d65b0
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/conf/local.conf.sample b/conf/local.conf.sample
index a7dae26..9cce692 100644
--- a/conf/local.conf.sample
+++ b/conf/local.conf.sample
@@ -1,4 +1,5 @@
-MACHINE ??= "evb-ast2500"
+#MACHINE ?= "evb-ast2500"
+MACHINE ??= "evb-ast2600"
 
 # Allow logging in if the user does not set the root password.
 EXTRA_IMAGE_FEATURES ?= "debug-tweaks"