Grid-launch updates to 2.0 and cleanup of old.

_ Use fields from GRID_LAUNCH_20 structure
  (See USE_GRID_LAUNCH_20 define, currently set to 0)
  "1" will require HCC support.
- Remove old DISABLE_GRID_LAUNCH support.

Change-Id: I584ce648d217251789a6283cf27feb24cb7dc8d1

include/hip_common.h

@@ -22,9 +22,6 @@ THE SOFTWARE.
 
 #pragma once
 
-// Disable use of grid_launch feature in HCC compiler.
-//#define DISABLE_GRID_LAUNCH
-
 // Common code included at start of every hip file.
 // Auto enable __HIP_PLATFORM_HCC__ if compiling with HCC
 // Other compiler (GCC,ICC,etc) need to set one of these macros explicitly