Rename hip/hip_hcc.h to hip/hip_ext.h (#1341)

* Rename hip/hip_hcc.h to hip/hip_ext.h

* Deprecate hip_hcc.h


[ROCm/hip-tests commit: 67e27b3603]

projects/hip-tests/samples/0_Intro/module_api_global/runKernel.cpp

@@ -25,7 +25,7 @@ THE SOFTWARE.
 #include <iostream>
 #include <fstream>
 #include <vector>
-#include <hip/hip_hcc.h>
+#include <hip/hip_ext.h>
 
 #define LEN 64
 #define SIZE LEN * sizeof(float)