tools arch kvm: Sync kvm headers with the kernel sources

To pick up the changes from:

  70f094f4 ("KVM: nVMX: Properly pad 'struct kvm_vmx_nested_state_hdr'")

That don't entail changes in tooling.

This silences these tools/perf build warnings:

  Warning: Kernel ABI header at 'tools/arch/x86/include/uapi/asm/kvm.h' differs from latest version at 'arch/x86/include/uapi/asm/kvm.h'
  diff -u tools/arch/x86/include/uapi/asm/kvm.h arch/x86/include/uapi/asm/kvm.h

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/arch/x86/include/uapi/asm/kvm.h

@@ -437,6 +437,8 @@ struct kvm_vmx_nested_state_hdr {
 		__u16 flags;
 	} smm;
 
+	__u16 pad;
+
 	__u32 flags;
 	__u64 preemption_timer_deadline;
 };