Trivial Typo's in bier comments/docs.

Change-Id: I3b3e868277d5caf6b1341814003a3bc5726c2df9
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
diff --git a/src/vnet/bier/bier_disp_entry.h b/src/vnet/bier/bier_disp_entry.h
index db381a8..59481f6 100644
--- a/src/vnet/bier/bier_disp_entry.h
+++ b/src/vnet/bier/bier_disp_entry.h
@@ -36,8 +36,8 @@
     CLIB_CACHE_LINE_ALIGN_MARK(cacheline0);
 
     /**
-     * The DPO contirubted from the per-payload protocol parents
-     * on cachline 1.
+     * The DPO contributed from the per-payload protocol parents
+     * on cacheline 1.
      */
     struct
     {