drm/xe/vf: Track writes to inaccessible registers from VF

drm/xe/vf: Track writes to inaccessible registers from VF

Only limited set of registers is accessible for the VF driver and
the hardware will silently drop writes to inaccessible registers.
To improve our VF driver lets intercept all such writes to warn
about such unexpected writes on debug builds or optionally allow
to provide some substitution (as a potential future extension).

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Gustavo Sousa <gustavo.sousa@intel.com>
Cc: Piotr Piórkowski <piotr.piorkowski@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240713142643.1242-2-michal.wajdeczko@intel.com