Remove cudaMemAccessFlagsProtRead as it is not supported by mem pools

include/rmm/mr/device/cuda_async_memory_resource.hpp

@@ -68,12 +68,12 @@ class cuda_async_memory_resource final : public device_memory_resource {
    * @brief Flags for specifying the memory pool accessibility from other devices.
    *
    * @note The default, `prot_none`, marks the pool's memory as private to the device in
-   * which it was created. `prot_read` and `prot_read_write` should only be used if memory
-   * sharing among devices is required.
+   * which it was created. `prod_read_write` should only be used if memory sharing among
+   * devices is required. Note that there is a `cudaMemAccessFlagsProtRead` documented,
+   * but memory pools don't support read-only, so it has been omitted.
    */
   enum class access_flags {
     prot_none       = 0,  ///< Default, make pool not accessible. (cudaMemAccessFlagsProtNone)
-    prot_read       = 1,  ///< Make pool read accessible. (cudaMemAccessFlagsProtRead)
     prot_read_write = 3   ///< Make pool read-write accessible. (cudaMemAccessFlagsProtReadWrite)
   };