Properly configure hipCUB dependency

The HIP backend of MGARDX required the use of hipCUB. This is often
installed with hip and will just be available, but it is not always.
In the case where it is installed separately, make sure it is
configured.

Author: kmorel

CMakeLists.txt

@@ -207,6 +207,12 @@ if (MGARD_ENABLE_HIP)
   target_compile_definitions(mgard-library PUBLIC MGARD_ENABLE_HIP)
   set (CMAKE_HIP_FLAGS  "${CMAKE_HIP_FLAGS} -w")
   set_source_files_properties(${MGARD_X_HIP_SRC} PROPERTIES LANGUAGE HIP)
+
+  # Find the required hipCUB packages, which is usually, but not always,
+  # installed with hip.
+  find_package(rocprim REQUIRED CONFIG)
+  find_package(hipcub REQUIRED CONFIG)
+  target_link_libraries(mgard-library PUBLIC hip::hipcub)
 endif()
 
 if (MGARD_ENABLE_SYCL)