drm/xe/pxp: Use the correct define in the set_property_funcs array

The define of the extension type was accidentally used instead of the
one of the property itself. They're both zero, so no functional issue,
but we should use the correct define for code correctness.

Fixes: 41a97c4a ("drm/xe/pxp/uapi: Add API to mark a BO as using PXP")
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://lore.kernel.org/r/20250522225401.3953243-6-daniele.ceraolospurio@intel.com