hw/i386/pc: Remove deprecated pc-q35-2.5 and pc-i440fx-2.5 machines

hw/i386/pc: Remove deprecated pc-q35-2.5 and pc-i440fx-2.5 machines

These machines has been supported for a period of more than 6 years.
According to our versioned machine support policy (see commit
ce80c4fa6ff "docs: document special exception for machine type
deprecation & removal") they can now be removed.

Remove the now unused empty pc_compat_2_5[] array.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-ID: <20250512083948.39294-10-philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>