Documentation: virt/kvm: remove unreferenced footnote

JIRA: https://issues.redhat.com/browse/RHEL-120168

commit 2bb0e39
Author: Paolo Bonzini <pbonzini@redhat.com>
Date:   Mon May 26 16:12:01 2025 -0400

    Documentation: virt/kvm: remove unreferenced footnote

    Replace it with just the URL.

    Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>

Author: Maxim Levitsky

Documentation/virt/kvm/x86/intel-tdx.rst

@@ -265,4 +265,4 @@ control flow is as follows:
 References
 ==========
 
-.. [1] https://www.intel.com/content/www/us/en/developer/tools/trust-domain-extensions/documentation.html
+https://www.intel.com/content/www/us/en/developer/tools/trust-domain-extensions/documentation.html