Add workaround for some ARM compilers that do not always generate aligned accesses for packed structures.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9098 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Include/IndustryStandard/Acpi10.h

@@ -67,7 +67,7 @@ typedef struct {
 /// The commond definition of QWORD, DWORD, and WORD
 /// Address Space Descriptors
 ///
-typedef struct {
+typedef PACKED struct {
   UINT8   Desc;
   UINT16  Len;
   UINT8   ResType;