Add release notes for the MicroBlaze backend.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144550 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html
index 6d0b535..8c803cd 100644
--- a/docs/ReleaseNotes.html
+++ b/docs/ReleaseNotes.html
@@ -977,6 +977,11 @@
 
   <p>PPC32/ELF va_arg was implemented.</p>
   <p>PPC32 initial support for .o file writing was implemented.</p>
+  <p>MicroBlaze scheduling itineraries were added that model the
+     3-stage and the 5-stage pipeline architectures. The 3-stage
+     pipeline model can be selected with <code>-mcpu=mblaze3</code> 
+     and the 5-stage pipeline model can be selected with 
+     <code>-mcpu=mblaze5</code>.</p>
   
 <ul>
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