kvm: x86: Fix vmwrite to SECONDARY_VM_EXEC_CONTROL

vmx_cpuid_tries to update SECONDARY_VM_EXEC_CONTROL in the VMCS, but
it will cause a vmwrite error on older CPUs because the code does not
check for the presence of CPU_BASED_ACTIVATE_SECONDARY_CONTROLS.

This will get rid of the following trace on e.g. Core2 6600:

vmwrite error: reg 401e value 10 (err 12)
Call Trace:
[<ffffffff8116e2b9>] dump_stack+0x40/0x57
[<ffffffffa020b88d>] vmx_cpuid_update+0x5d/0x150 [kvm_intel]
[<ffffffffa01d8fdc>] kvm_vcpu_ioctl_set_cpuid2+0x4c/0x70 [kvm]
[<ffffffffa01b8363>] kvm_arch_vcpu_ioctl+0x903/0xfa0 [kvm]

Fixes: feda805
Cc: stable@vger.kernel.org
Reported-by: Zdenek Kaspar <zkaspar82@gmail.com>
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -8989,7 +8989,8 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 			best->ebx &= ~bit(X86_FEATURE_INVPCID);
 	}
 
-	vmcs_set_secondary_exec_control(secondary_exec_ctl);
+	if (cpu_has_secondary_exec_ctrls())
+		vmcs_set_secondary_exec_control(secondary_exec_ctl);
 
 	if (static_cpu_has(X86_FEATURE_PCOMMIT) && nested) {
 		if (guest_cpuid_has_pcommit(vcpu))