Revert "Always set WP in CR0."

Revert "Always set WP in CR0."

This reverts SVN r18960 / git commit
8e496a7abcb78c36b0af47ed473096ef7f171606.

The patch series had been fully reviewed on edk2-devel, but it got
committed as a single squashed patch. Revert it for now.

Link: http://thread.gmane.org/gmane.comp.bios.edk2.devel/4951
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18977 6f19259b-4bc3-4df7-8a09-765794883524