AST2500: Add AST2500 evaluation board layer

The AST2500 is an ARM SOC made by Aspeed.

This layer is a stub; there are a couple missing bits of support
from the kernel and u-boot.

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/meta-openbmc-machines/meta-evb/meta-evb-aspeed/meta-evb-ast2500/conf/conf-notes.txt b/meta-openbmc-machines/meta-evb/meta-evb-aspeed/meta-evb-ast2500/conf/conf-notes.txt
new file mode 100644
index 0000000..9b3c01a
--- /dev/null
+++ b/meta-openbmc-machines/meta-evb/meta-evb-aspeed/meta-evb-ast2500/conf/conf-notes.txt
@@ -0,0 +1,2 @@
+Common targets are:
+     obmc-phosphor-image