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_hdr_inlines.h b/src/vnet/bier/bier_hdr_inlines.h
index 81e196d..e824997 100644
--- a/src/vnet/bier/bier_hdr_inlines.h
+++ b/src/vnet/bier/bier_hdr_inlines.h
@@ -48,7 +48,7 @@
 #define BIER_HDR_1ST_NIBBLE_VALUE 0x5
 
 /**
- * Mask and shift values for fields in the headers trainling word
+ * Mask and shift values for fields in the headers training word
  */
 #define BIER_HDR_PROTO_FIELD_MASK   0x003f
 #define BIER_HDR_OAM_FIELD_MASK     0xc000