x86/fpu: Replace KVMs xstate component clearing

In order to prepare for the support of dynamically enabled FPU features,
move the clearing of xstate components to the FPU core code.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/20211013145322.399567049@linutronix.de