[ARM] Fix comment typo

Author: ostannard

llvm/lib/Target/ARM/ARMISelLowering.cpp

@@ -2408,8 +2408,8 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
     isTailCall = false;
 
   // For both the non-secure calls and the returns from a CMSE entry function,
-  // the function needs to do some extra work afte r the call, or before the
-  // return, respectively, thus it cannot end with atail call
+  // the function needs to do some extra work after the call, or before the
+  // return, respectively, thus it cannot end with a tail call
   if (isCmseNSCall || AFI->isCmseNSEntryFunction())
     isTailCall = false;