drm/i915: Noop lrc_init_wa_ctx() on recent/future platforms

Except for graphics version 8 and 9, nothing is done in
lrc_init_wa_ctx(). Assume this won't be needed on future platforms as
well and remove the warning.

Note that this function is not called for anything below version 8 since
those don't use either guc or execlist, i.e. HAS_EXECLISTS() is false.

Reviewed-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220907230841.1703574-1-lucas.demarchi@intel.com