KVM: x86: add missing "depends on KVM"

Support for KVM software-protected VMs should not be configurable,
if KVM is not available at all.

Fixes: 89ea60c ("KVM: x86: Add support for "protected VMs" that can utilize private memory")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: bonzini

arch/x86/kvm/Kconfig

@@ -77,7 +77,7 @@ config KVM_WERROR
 config KVM_SW_PROTECTED_VM
 	bool "Enable support for KVM software-protected VMs"
 	depends on EXPERT
-	depends on X86_64
+	depends on KVM && X86_64
 	select KVM_GENERIC_PRIVATE_MEM
 	help
 	  Enable support for KVM software-protected VMs.  Currently "protected"