Docs: Fix typo: NoIntinerary -> NoItinerary.

llvm-svn: 194976
diff --git a/llvm/docs/WritingAnLLVMBackend.rst b/llvm/docs/WritingAnLLVMBackend.rst
index a2a0f6c..0d29210 100644
--- a/llvm/docs/WritingAnLLVMBackend.rst
+++ b/llvm/docs/WritingAnLLVMBackend.rst
@@ -955,7 +955,7 @@
 Instruction itineraries can be queried using MCDesc::getSchedClass(). The
 value can be named by an enumemation in llvm::XXX::Sched namespace generated
 by TableGen in XXXGenInstrInfo.inc. The name of the schedule classes are
-the same as provided in XXXSchedule.td plus a default NoIntinerary class.
+the same as provided in XXXSchedule.td plus a default NoItinerary class.
 
 Instruction Relation Mapping
 ----------------------------