x86/sev: Fix noinstr for vc_ghcb_invalidate()

vmlinux.o: warning: objtool: __sev_put_ghcb()+0x88: call to __memset() leaves .noinstr.text section
vmlinux.o: warning: objtool: __sev_es_nmi_complete()+0x39: call to __memset() leaves .noinstr.text section

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210624095148.250770465@infradead.org