drm/i915/xe2lpd: Register DE_RRMR has been removed

Do not read DE_RRMR register after display version 20. This register
contains display state information during GFX state dumps.

Bspec: 69456
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230919192128.2045154-9-lucas.demarchi@intel.com