DuetPkg: Fix build break caused by EFI_SPECIFICATION_VERSION usage
DuetPkg: Fix build break caused by EFI_SPECIFICATION_VERSION usage

The EFI_SPECIFICATION_VERSION MACRO is no longer defined in edk2
builds, and this module does not need to support the older < UEFI 2.0
code path.

git-svn-id: 5648d1bec6962b0a6d1d1b40eba8cf5cdb62da3d@10096 6f19259b-4bc3-4df7-8a09-765794883524

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2