Magma isn't needed in cpu build (#59619)
Summary:
Fix incorrect logic in windows CPU build script
VERSION_SUFFIX shouldn't be cpu
https://github.com/pytorch/pytorch/pull/59618/checks?check_run_id=2771591019
Pull Request resolved: https://github.com/pytorch/pytorch/pull/59619
Reviewed By: samestep
Differential Revision: D29000213
Pulled By: seemethere
fbshipit-source-id: fcc474967e281fbf9be69f14c0aedfd01820573f
