Misc typos fixes in ./lib folder

Summary: Found via `codespell -q 3 -I ../clang-whitelist.txt -L uint,importd,crasher,gonna,cant,ue,ons,orign,ned`

Reviewers: teemperor

Reviewed By: teemperor

Subscribers: teemperor, jholewinski, jvesely, nhaehnle, whisperity, jfb, cfe-commits

Differential Revision: https://reviews.llvm.org/D55475

llvm-svn: 348755
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 116678a..38d9a52 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -431,7 +431,7 @@
   switch (LangOpts.getDefaultFPContractMode()) {
   case LangOptions::FPC_Off:
     // Preserve any contraction performed by the front-end.  (Strict performs
-    // splitting of the muladd instrinsic in the backend.)
+    // splitting of the muladd intrinsic in the backend.)
     Options.AllowFPOpFusion = llvm::FPOpFusion::Standard;
     break;
   case LangOptions::FPC_On: