drm/doc: Document device wedged event

drm/doc: Document device wedged event

Add documentation for device wedged event in a new "Device wedging"
chapter. This describes basic definitions, prerequisites and consumer
expectations along with an example.

 v8: Improve introduction (Christian, Rodrigo)
 v9: Add prerequisites section (Christian)
v10: Clarify mmap cleanup and consumer prerequisites (Christian, Aravind)
v11: Reference wedged event in device reset chapter (André)
v12: Refine consumer expectations and terminologies (Xaver, Pekka)

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250204070528.1919158-3-raag.jadav@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>