meta-ibm: move all meta-witherspoon metadata

The metadata common to all IBM systems is confusingly split between
meta-ibm and meta-witherspoon.  Move everything to meta-ibm.

The meta-ibm README is re-written to more accurately reflect the scope
of the layer.

Allow the configuration samples (bblayers.conf.sample,
local.conf.sample) to be sourced from either meta-ibm or
meta-witherspoon until such a time that any workflows and tooling have
had the opportunity to move to meta-ibm.

Change-Id: I50e2ecdd510b5a8f2ba82f79c4e0dc1b9f98892b
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/recipes-phosphor/logging/ibm-logging_git.bb b/recipes-phosphor/logging/ibm-logging_git.bb
index 50be5da..cb48849 100644
--- a/recipes-phosphor/logging/ibm-logging_git.bb
+++ b/recipes-phosphor/logging/ibm-logging_git.bb
@@ -30,6 +30,9 @@
 PACKAGECONFIG ??= ""
 PACKAGECONFIG[policy-interface] = "--enable-policy-interface, --disable-policy-interface,,"
 
+PACKAGECONFIG_ibm-ac-server = "policy-interface"
+PACKAGECONFIG_mihawk = "policy-interface"
+
 SERVICE = "com.ibm.Logging.service"
 DBUS_SERVICE_${PN} += "${SERVICE}"