ArmPkg/ArmMmuLib: use correct return type for exported functions

The routines ArmConfigureMmu(), SetMemoryAttributes() [*] and the
various set/clear read-only/no-exec routines are declared as returning
EFI_STATUS in the respective header files, so align the definitions with
that.

* SetMemoryAttributes() is declared in the wrong header (and defined in
  ArmMmuLib for AARCH64 and in CpuDxe for ARM)

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

ArmPkg/Library/ArmMmuLib/Arm/ArmMmuLibCore.c

@@ -406,40 +406,41 @@ ArmConfigureMmu (
   return RETURN_SUCCESS;
 }
 
-RETURN_STATUS
+
+EFI_STATUS
 ArmSetMemoryRegionNoExec (
   IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
   IN  UINT64                    Length
   )
 {
-  return RETURN_UNSUPPORTED;
+  return EFI_UNSUPPORTED;
 }
 
-RETURN_STATUS
+EFI_STATUS
 ArmClearMemoryRegionNoExec (
   IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
   IN  UINT64                    Length
   )
 {
-  return RETURN_UNSUPPORTED;
+  return EFI_UNSUPPORTED;
 }
 
-RETURN_STATUS
+EFI_STATUS
 ArmSetMemoryRegionReadOnly (
   IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
   IN  UINT64                    Length
   )
 {
-  return RETURN_UNSUPPORTED;
+  return EFI_UNSUPPORTED;
 }
 
-RETURN_STATUS
+EFI_STATUS
 ArmClearMemoryRegionReadOnly (
   IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
   IN  UINT64                    Length
   )
 {
-  return RETURN_UNSUPPORTED;
+  return EFI_UNSUPPORTED;
 }
 
 RETURN_STATUS