x86/fpu: Rename initstate copy functions

Again this not a copy. It's restoring register state from kernel memory.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121454.816581630@linutronix.de