drm/xe: Don't raise error on fused-off media

drm/xe: Don't raise error on fused-off media

It's legitimate for the media GMD_ID register to read back as 0x0 if
media functionality is fused off or otherwise not present on the
platform.  Avoid printing an "unknown media version" error message for
this case.

Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://lore.kernel.org/r/20230614205202.3376752-3-matthew.d.roper@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>