KVM: arm64: Make symbol '_kvm_host_prot_finalize' static

The sparse tool complains as follows:

arch/arm64/kvm/arm.c:1900:6: warning:
 symbol '_kvm_host_prot_finalize' was not declared. Should it be static?

This symbol is not used outside of arm.c, so this
commit marks it static.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Xu Jia <xujia39@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1617176179-31931-1-git-send-email-xujia39@huawei.com

arch/arm64/kvm/arm.c

@@ -1897,7 +1897,7 @@ static int init_hyp_mode(void)
 	return err;
 }
 
-void _kvm_host_prot_finalize(void *discard)
+static void _kvm_host_prot_finalize(void *discard)
 {
 	WARN_ON(kvm_call_hyp_nvhe(__pkvm_prot_finalize));
 }