Updates docs for hipHcc* functions, move to header

[ROCm/hip commit: 83140f8423]

projects/hip/include/hcc_detail/hcc_acc.h

@@ -7,11 +7,15 @@
 #include <hc.hpp>
 /**
  * @brief Return hc::accelerator associated with the specified deviceId
+ * @return #hipSuccess, #hipErrorInvalidDevice
  */
 hipError_t hipHccGetAccelerator(int deviceId, hc::accelerator *acc);
 
 /**
  * @brief Return hc::accelerator_view associated with the specified stream
+ *
+ * If stream is 0, the accelerator_view for the default stream is returned.
+ * @return #hipSuccess
  */
 hipError_t hipHccGetAcceleratorView(hipStream_t stream, hc::accelerator_view **av);
 #endif