Fix -Wdocumentation warning. (#3715)

Summary:
Pull Request resolved: #3715

.

Reviewed By: mergennachin

Differential Revision: D57711383

fbshipit-source-id: 8d7427743775abe800b41b192ed872560b75b4d5

Author: shoumikhin

runtime/backend/interface.h

@@ -67,7 +67,6 @@ class PyTorchBackendInterface {
    *     memory.
    * @param[in] compile_specs The exact same compiler specification that
    *     was used ahead-of-time to produce `processed`.
-   * @param[in] memory_allocator The allocator to allocate from if necessary.
    *
    * @returns On success, an opaque handle representing the the method
    *     implemented by the delegate. This handle is passed to `execute()` and
@@ -126,7 +125,7 @@ class BackendRegistry {
   /**
    * Registers the Backend object (i.e. string name and PyTorchBackendInterface
    * pair) so that it could be called via the name during the runtime.
-   * @param[in] name Name of the user-defined backend delegate.
+   * @param[in] backend Backend object of the user-defined backend delegate.
    * @retval Error code representing whether registration was successful.
    */
   __ET_NODISCARD Error register_backend(const Backend& backend);