x86/fpu: Make os_xrstor_booting() private

It's only required in the xstate init code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011539.455836597@linutronix.de
2 files changed