drm/xe/uapi: Kill exec_queue_set_property

All the properties should be immutable and set upon exec_queue creation
using the existent extension. So, let's kill this useless and dangerous
uapi.

Cc: Francois Dugast <francois.dugast@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Francois Dugast <francois.dugast@intel.com>