Add new function attribute - noredzone.

Update code generator to use this attribute and remove DisableRedZone target option.
Update llc to set this attribute when -disable-red-zone command line option is used.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72894 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetOptions.h

@@ -117,10 +117,6 @@ namespace llvm {
   /// wth earlier copy coalescing.
   extern bool StrongPHIElim;
 
-  /// DisableRedZone - This flag disables use of the "Red Zone" on
-  /// targets which would otherwise have one.
-  extern bool DisableRedZone;
-
 } // End llvm namespace
 
 #endif