drm/xe/kunit: Remove handling of XE_TEST_SUBPLATFORM_ANY

The only user passing XE_TEST_SUBPLATFORM_ANY is
xe_pci_fake_device_init_any(), but then the function would return
earlier when handling XE_TEST_PLATFORM_ANY. Platforms without a
subplatform use XE_SUBPLATFORM_NONE.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://lore.kernel.org/r/20231129232807.1499826-3-lucas.demarchi@intel.com
Link: https://lore.kernel.org/r/20231129232807.1499826-6-lucas.demarchi@intel.com
Link: https://lore.kernel.org/r/20231205133954.2089546-1-lucas.demarchi@intel.com


Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>