Fix spelling mistakes in Hexagon target comments. NFC.

Identified by Pedro Giffuni in PR27636.

llvm-svn: 287248
diff --git a/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp b/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
index 36b6e72..50f529e 100644
--- a/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
+++ b/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
@@ -895,7 +895,7 @@
 
   int64_t MaxBytesToFill = 15;
 
-  // if there is an arguement
+  // if there is an argument
   if (getLexer().isNot(AsmToken::EndOfStatement)) {
     const MCExpr *Value;
     SMLoc ExprLoc = L;