drm/xe/pxp: Don't allow PXP on older PTL GSC FWs

drm/xe/pxp: Don't allow PXP on older PTL GSC FWs

On PTL, older GSC FWs have a bug that can cause them to crash during
PXP invalidation events, which leads to a complete loss of power
management on the media GT. Therefore, we can't use PXP on FWs that
have this bug, which was fixed in PTL GSC build 1396.

Fixes: b1dcec9bd8a1 ("drm/xe/ptl: Enable PXP for PTL")
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Julia Filipchuk <julia.filipchuk@intel.com>
Reviewed-by: Julia Filipchuk <julia.filipchuk@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/20260324153718.3155504-10-daniele.ceraolospurio@intel.com