Add GFX908 specific changes to HIP (#1229)

* Add GFX908 specific for HIP

* Fix missing __halfTest in hipTestNativeHalf


[ROCm/hip commit: b754de37c1]

projects/hip/tests/src/deviceLib/hipTestHalf.cpp

@@ -28,7 +28,7 @@ THE SOFTWARE.
 
 #include "test_common.h"
 
-#if __HIP_ARCH_GFX803__ || __HIP_ARCH_GFX900__ || __HIP_ARCH_GFX906__
+#if __HIP_ARCH_GFX803__ || __HIP_ARCH_GFX900__ || __HIP_ARCH_GFX906__ || __HIP_ARCH_GFX908__
 
 __global__
 void __halfMath(bool* result, __half a) {