Fix a build error on signed/unsigned comparison

Change-Id: Ic79eb4c3ec5c6fd36cea7c4810d990619f08b9e1

rocclr/hip_platform.cpp

@@ -878,7 +878,7 @@ hipError_t ihipOccupancyMaxActiveBlocksPerMultiprocessor(
     }
   }
   else {
-    if (inputBlockSize > device.info().maxWorkGroupSize_ ||
+    if (inputBlockSize > int(device.info().maxWorkGroupSize_) ||
             inputBlockSize == 0) {
       // The user wrote the kernel to work with a workgroup size
       // bigger than this hardware can support. Or they do not care