drm/i915: Don't do WaFbcTurnOffFbcWatermark for glk

GLK supposedly does not need WaFbcTurnOffFbcWatermark,
so let's not apply it.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708131223.9519-2-ville.syrjala@linux.intel.com


Reviewed-by: José Roberto de Souza <jose.souza@intel.com>