Support generic disabling of all XSAVE features

From: Andi Kleen
Date: Tue Sep 19 2017 - 18:26:56 EST

For performance testing and debugging it can be useful to disable XSAVE
features individually. This patchkit hooks up XSAVE with the
generic clearcpuid=... option, so that disabling a CPUID feature
automatically disables the respective XSAVE feature.

It also cleans up CPUID dependency management. Currently it's
possible to generate configurations with cleacpuid that crash.

It replaces an earlier patchkit that did this with special
case options.

Initial post
Work around broken lguest by exporting set_cpu_cap
Repost with cover letter
Repost. No changes to code.
Rebase to latest tree. Repost.
Fix dependency algorithm. Clean dups in table. Rebase.
Rebase. No changes to code.