KVM: x86: Drop pointless exports of kvm_arch_xxx() hooks

Drop the exporting of several kvm_arch_xxx() hooks that are only called
from arch-neutral code, i.e. that are only called from kvm.ko.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Sean Christopherson <[e-mail]>
Signed-off-by: Paolo Bonzini <[e-mail]>

arch/x86/kvm/x86.c

···
 	if (atomic_inc_return(&kvm->arch.noncoherent_dma_count) == 1)
 		kvm_noncoherent_dma_assignment_start_or_stop(kvm);
 }
-EXPORT_SYMBOL_GPL(kvm_arch_register_noncoherent_dma);
 
 void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm)
 {
 	if (!atomic_dec_return(&kvm->arch.noncoherent_dma_count))
 		kvm_noncoherent_dma_assignment_start_or_stop(kvm);
 }
-EXPORT_SYMBOL_GPL(kvm_arch_unregister_noncoherent_dma);
 
 bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
 {
···
 {
 	return (vcpu->arch.msr_kvm_poll_control & 1) == 0;
 }
-EXPORT_SYMBOL_GPL(kvm_arch_no_poll);
 
 #ifdef CONFIG_KVM_GUEST_MEMFD
 /*