added pack(1) for EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR, since it will cross modules through protocol.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@6169 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Include/IndustryStandard/Acpi10.h

@@ -59,7 +59,10 @@ typedef struct {
 ///
 #define ACPI_TIMER_FREQUENCY       3579545
 
-
+//
+// Ensure proper structure formats
+//
+#pragma pack(1)
 //
 // The commond definition of QWORD, DWORD, and WORD
 // Address Space Descriptors
@@ -77,6 +80,8 @@ typedef struct {
   UINT64  AddrLen;
 } EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR;
 
+#pragma pack()
+
 typedef struct {
   UINT8 Desc;
   UINT8 Checksum;