Revert "acpu: fix krait variant export"

This reverts commit dea0e6576a61c1a94977dd44c5bb135da1e2ce99.
Revert "acpu: krait_variant: add detection for unknown pvs"

This reverts commit d49abcb3eda1e2109f70ba30c874b22f2a8a5827.
Revert "acpu: export krait variant to debugfs"

This reverts commit 4a8019a5cdcd19a42dfe4eeaef791d1a2e837a3b.