meta-ampere: Initial AmpereOne(TM) Mt. Mitchell's non-DC-SCM BMC support

Add new Mt.Mitchell platform with basic features so that it can be
compiled and works.

Tested:
1. Compile for Mt.Mitchell successful.
2. Flash and check for the firmware can boot on the Mt.Mitchell
non-DC-SCM system without issue

Signed-off-by: Chanh Nguyen <chanh@os.amperecomputing.com>
Change-Id: I8dc9db9029b27c0c6325c31d368cdbb614a3c8b6
diff --git a/meta-ampere/meta-mitchell/conf/layer.conf b/meta-ampere/meta-mitchell/conf/layer.conf
new file mode 100644
index 0000000..3855afb
--- /dev/null
+++ b/meta-ampere/meta-mitchell/conf/layer.conf
@@ -0,0 +1,11 @@
+# We have a conf and classes directory, add to BBPATH
+BBPATH .= ":${LAYERDIR}"
+
+# We have recipes-* directories, add to BBFILES
+BBFILES += "${LAYERDIR}/recipes-*/*/*.bb \
+            ${LAYERDIR}/recipes-*/*/*.bbappend"
+
+BBFILE_COLLECTIONS += "mitchell-layer"
+BBFILE_PATTERN_mitchell-layer := "^${LAYERDIR}/"
+LAYERSERIES_COMPAT_mitchell-layer = "kirkstone langdale"
+