StandaloneMmPkg/Core: drop support for dispatching FVs into MM

Remove the support that permits calls into the MM context to dispatch
firmware volumes that are not part of the initial standalone MM firmware
volume.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: "Yao, Jiewen" <jiewen.yao@intel.com>
Reviewed-by: Achin Gupta <achin.gupta@arm.com>

StandaloneMmPkg/Core/StandaloneMmCore.h

@@ -635,28 +635,6 @@ MmDriverDispatchHandler (
 
   @return Status Code
 
-**/
-EFI_STATUS
-EFIAPI
-MmFvDispatchHandler (
-  IN     EFI_HANDLE               DispatchHandle,
-  IN     CONST VOID               *Context,        OPTIONAL
-  IN OUT VOID                     *CommBuffer,     OPTIONAL
-  IN OUT UINTN                    *CommBufferSize  OPTIONAL
-  );
-
-/**
-  This function is the main entry point for an MM handler dispatch
-  or communicate-based callback.
-
-  @param  DispatchHandle  The unique handle assigned to this handler by MmiHandlerRegister().
-  @param  Context         Points to an optional handler context which was specified when the handler was registered.
-  @param  CommBuffer      A pointer to a collection of data in memory that will
-                          be conveyed from a non-MM environment into an MM environment.
-  @param  CommBufferSize  The size of the CommBuffer.
-
-  @return Status Code
-
 **/
 EFI_STATUS
 EFIAPI