x86/coco: Mark cc_platform_has() and descendants noinstr

Those will be used in code regions where instrumentation is not allowed
so mark them as such.

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230328201712.25852-2-bp@alien8.de