Docs: Fix typo: NoIntinerary -> NoItinerary.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194976 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/WritingAnLLVMBackend.rst b/docs/WritingAnLLVMBackend.rst
index a2a0f6c..0d29210 100644
--- a/docs/WritingAnLLVMBackend.rst
+++ b/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
 ----------------------------