MdeModulePkg: Fix Memory Attributes table type issue

According to the spec, each entry in the Memory
Attributes table shall have the same type as
the region it was carved out of in the UEFI memory map.
The current attribute uses RTData for PE Data, but
it should be RTCode.

This patch fixed the issue. It is validated with or
without PropertiesTable.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: "Yao, Jiewen" <jiewen.yao@intel.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdeModulePkg/Core/Dxe/Misc/MemoryAttributesTable.c

@@ -72,8 +72,6 @@ CoreGetMemoryMapPropertiesTable (
 
 extern EFI_PROPERTIES_TABLE  mPropertiesTable;
 
-BOOLEAN         mIsConstructingMemoryAttributesTable = FALSE;
-
 /**
   Install MemoryAttributesTable.
 
@@ -105,8 +103,6 @@ InstallMemoryAttributesTable (
     return ;
   }
 
-  mIsConstructingMemoryAttributesTable = TRUE;
-
   MemoryMapSize = 0;
   MemoryMap = NULL;
   Status = CoreGetMemoryMapPropertiesTable (
@@ -181,8 +177,6 @@ InstallMemoryAttributesTable (
 
   Status = gBS->InstallConfigurationTable (&gEfiMemoryAttributesTableGuid, MemoryAttributesTable);
   ASSERT_EFI_ERROR (Status);
-
-  mIsConstructingMemoryAttributesTable = FALSE;
 }
 
 /**