drm/i915/fbc: Disable fbc by default on all glk+

We're missing a workaround in the fbc code for all glk+ platforms
which can cause corruption around the top of the screen. So
enabling fbc by default is a bad idea. I'm not keen to backport
the w/a so let's start by disabling fbc by default on all glk+.
We'll lift the restriction once the w/a is in place.

Cc: stable@vger.kernel.org
Cc: Daniel Drake <drake@endlessm.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Jian-Hong Pan <jian-hong@endlessm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191127201222.16669-2-ville.syrjala@linux.intel.comReviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/i915/display/intel_fbc.c

@@ -1284,7 +1284,7 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv)
 		return 0;
 
 	/* https://bugs.freedesktop.org/show_bug.cgi?id=108085 */
-	if (IS_GEMINILAKE(dev_priv))
+	if (INTEL_GEN(dev_priv) >= 10 || IS_GEMINILAKE(dev_priv))
 		return 0;
 
 	if (IS_BROADWELL(dev_priv) || INTEL_GEN(dev_priv) >= 9)