drm/xe/hwmon: Expose GPU PCIe temperature

drm/xe/hwmon: Expose GPU PCIe temperature

Expose GPU PCIe average temperature and its limits via hwmon sysfs entry
temp5_xxx.
Update Xe hwmon sysfs documentation for this.

v2: Update kernel version in Xe hwmon documentation. (Raag)

v3:
 - Address review comments from Raag.
 - Remove redundant debug log.
 - Update kernel version in Xe hwmon documentation. (Raag)

v4:
 - Address review comments from Raag.
 - Group new temperature attributes with existing temperature attributes
   as per channel index in Xe hwmon documentation.
 - Use TEMP_MASK instead of TEMP_MASK_MAILBOX.
 - Add PCIE_SENSOR_MASK which uses REG_FIELD_GET as replacement of
   PCIE_SENSOR_SHIFT.

v5:
 - Address review comments from Raag.
 - Use REG_FIELD_GET to get PCIe temperature.
 - Move PCIE_SENSOR_GROUP_ID and PCIE_SENSOR_MASK to xe_pcode_api.h
 - Cosmetic change.

Signed-off-by: Karthik Poosa <karthik.poosa@intel.com>
Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Link: https://patch.msgid.link/20260112203521.1014388-4-karthik.poosa@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>