-Revert the rest of the masked midtexture clipping code from r3684.

git-svn-id: http://odamex.net/svn/root/branches/persdiv@3689 b0bcef46-2027-0410-bd56-ab726e9a1d04
Merge remote-tracking branch 'svn/persdiv' into 32bpp-persdiv