KVM: VMX: Directly use VMX capabilities helper to detect RDTSCP support

Use cpu_has_vmx_rdtscp() directly when computing secondary exec controls
and drop the now defunct vmx_rdtscp_supported().

No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

@@ -1687,11 +1687,6 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu)
 	vmx_clear_hlt(vcpu);
 }
 
-static bool vmx_rdtscp_supported(void)
-{
-	return cpu_has_vmx_rdtscp();
-}
-
 /*
  * Swap MSR entry in host/guest MSR entry array.
  */
@@ -4073,7 +4068,7 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
 		}
 	}
 
-	if (vmx_rdtscp_supported()) {
+	if (cpu_has_vmx_rdtscp()) {
 		bool rdtscp_enabled = guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP);
 		if (!rdtscp_enabled)
 			exec_control &= ~SECONDARY_EXEC_RDTSCP;