Update docs/how-to/hip_porting_guide.rst

Co-authored-by: Julia Jiang <[email protected]>

Author: randyh62

docs/how-to/hip_porting_guide.rst

@@ -30,7 +30,7 @@ General Tips
 --------------------------------------------------------------------------------
 
 * ``hipDeviceptr_t`` is a ``void*`` and treated like a raw pointer, while ``CUdevicptr``
-  is an ``unsigned long long`` and treated as a device memory handle. 
+  is an ``unsigned int`` and treated as a device memory handle. 
 * Starting to port on an NVIDIA machine is often the easiest approach, as the
   code can be tested for functionality and performance even if not fully ported
   to HIP.