[doc]shfl*sync update

1. Updated FAQ with shft*sync not supported hip_faq.md
2. Corrected some of input parameter description in hcc_details/hip_runtime_api.h
3. Redirect shfl*() to shfl_*_sync() for nvcc path where CUDA > 9.0

Change-Id: I3d8184db5fcc622852c9bad96b706348e8dfc16c

docs/markdown/hip_faq.md

@@ -239,4 +239,7 @@ $HIP/include/hip/hcc_detail/host_defines.h
 Or pass "-DGENERIC_GRID_LAUNCH=0" to hipcc at application compilation time.
 
 ### What is maximum limit of Generic Grid Launch parameters (grid and block)?
-Product of (grid.x and block.x), (grid.y and block.y) or (grid.z and block.z) should always be less than UINT_MAX.
+Product of (grid.x and block.x), (grid.y and block.y) or (grid.z and block.z) should always be less than UINT_MAX.
+
+### Are __shfl_*_sync functions supported on HIP platform?
+__shfl_*_sync is not supported on HIP but for nvcc path CUDA 9.0 and above all shuffle calls get redirected to it's sync version.