Revert "MdePkg/BaseLib.h: Update IA32_CR4 structure for 5-level paging"

Revert "MdePkg/BaseLib.h: Update IA32_CR4 structure for 5-level paging"

This reverts commit 7c5010c7f88b790f4524c4a5311819e3af5e2752.
Commit
7c5010c7f8 MdePkg/BaseLib.h: Update IA32_CR4 structure for 5-level paging
technically breaks the EDKII development process documented in
https://github.com/tianocore/tianocore.github.io/wiki/EDK-II-Development-Process
and Maintainers.txt in EDKII repo root directory.

The voilation is commit 7c5010c7f8 doesn't have a Reviewed-by or
Acked-by from MdePkg maintainers.

Signed-off-by: Ray Ni <ray.ni@intel.com>