drm/xe/ptl: Add PTL platform definition

PTL is an integrated GPU based on the Xe3 architecture.

v2: explicitly turn off display until display patches land.

Bspec: 72574
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Haridhar Kalvala <haridhar.kalvala@intel.com>
Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>
Reviewed-by: Shekhar Chauhan <shekhar.chauhan@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241008013509.61233-6-matthew.s.atwood@intel.com