ibm: Add a basic README

Most OE metadata repositories have a README.  Add a basic one for
meta-ibm.

meta-ibm never really had a clear direction of what it was supposed to
be, so give it one.

The top level meta-ibm will be a distro policy layer for IBM branded
servers.  Subtrees will be BSPs (and possibly additional distro policy)
for the components that make up the servers (BMCs and planars).

Note that meta-palmetto and meta-romulus are missing.  These are
OpenPOWER reference platforms and not IBM branded servers.  As such,
meta-palmetto and meta-romulus will be moved to meta-openpower.

(From meta-ibm rev: 8120f7c441f0599293cd05ae39ee852bfc52c482)

Change-Id: I6b0a446dd476188ff10d7c710a1c3ecb3eb4f754
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/meta-ibm/README b/meta-ibm/README
new file mode 100644
index 0000000..14aa748
--- /dev/null
+++ b/meta-ibm/README
@@ -0,0 +1,26 @@
+Collection of BSP and distro layers for IBM branded servers.
+
+This repository contains a set of distro policy for IBM branded servers:
+
+conf/
+classes/
+recipes-*/
+
+BSP layer(s) for the following IBM service processors:
+FSP-2: meta-fsp2
+
+BSP layer(s) for the following IBM branded servers:
+Witherspoon: meta-witherspoon
+Z: meta-z
+
+Subsequent description applies to the distro policy for IBM systems only in
+conf, classes, and recipes-*, for description of the BSP layers consult the
+README files there.
+
+Dependencies
+============
+
+This layer depends on:
+
+  URI: https://github.com/openbmc/meta-phosphor
+  branch: master