README: Clarify where to send patches

There is still a great deal of confusion over where patches for the
various components of the poky repository should be sent. Attempt to
mitigate this by including a blurb in the poky README similar to what
other layers and repositories do.

V2: Call out the special care required when dealing with the scripts
    directory per Saul Wold's recommendation.

V3: Recommend applying patches to oe-core prior to sending patches to
    the oe-core mailing list.

(From meta-yocto rev: d2747240e75ca0d43f569161694799c3d5d23014)

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Richard Purdie <richard.purdie@intel.com>
CC: Paul Gortmaker <paul.gortmaker@windriver.com>
CC: Paul Eggleton <paul.eggleton@linux.intel.com>
CC: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

README

@@ -27,3 +27,23 @@ DISTRO = "") and contains only emulated machine support.
 For information about OpenEmbedded, see the OpenEmbedded website:
     http://www.openembedded.org/
 
+Where to Send Patches
+=====================
+
+As Poky is an integration repository, patches against the various components
+should be sent to their respective upstreams.
+
+bitbake:
+    bitbake-devel@lists.openembedded.org
+
+meta-yocto:
+    poky@yoctoproject.org
+
+Most everything else should be sent to the OpenEmbedded Core mailing list.  If
+in doubt, check the oe-core git repository for the content you intend to modify.
+Before sending, be sure the patches apply cleanly to the current oe-core git
+repository.
+    openembedded-core@lists.openembedded.org
+
+Note: The scripts directory should be treated with extra care as it is a mix
+      of oe-core and poky-specific files.