drm/xe/xe_survivability: Add support for Runtime survivability mode

drm/xe/xe_survivability: Add support for Runtime survivability mode

Certain runtime firmware errors can cause the device to be in a unusable
state requiring a firmware flash to restore normal operation.
Runtime Survivability Mode indicates firmware flash is necessary by
wedging the device and exposing survivability mode sysfs.

The below sysfs is an indication that device is in survivability mode

/sys/bus/pci/devices/<device>/survivability_mode

v2: Fix kernel-doc (Umesh)
v3: Add user friendly dmesg (Frank)

Signed-off-by: Riana Tauro <riana.tauro@intel.com>
Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Link: https://lore.kernel.org/r/20250826063419.3022216-7-riana.tauro@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>