drm/i915: Fix per-pixel alpha with CCS

We forgot to set .has_alpha=true for the A+CCS formats when the code
started to consult .has_alpha. This manifests as A+CCS being treated
as X+CCS which means no per-pixel alpha blending. Fix the format
list appropriately.

Cc: stable@vger.kernel.org
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Heinrich Fink <heinrich.fink@daqri.com>
Reported-by: Heinrich Fink <heinrich.fink@daqri.com>
Tested-by: Heinrich Fink <heinrich.fink@daqri.com>
Fixes: b208152556 ("drm/i915: Add plane alpha blending support, v2.")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190603142500.25680-1-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
(cherry picked from commit 38f300410f)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_display.c

@@ -2432,10 +2432,14 @@ static unsigned int intel_fb_modifier_to_tiling(u64 fb_modifier)
  * main surface.
  */
 static const struct drm_format_info ccs_formats[] = {
-	{ .format = DRM_FORMAT_XRGB8888, .depth = 24, .num_planes = 2, .cpp = { 4, 1, }, .hsub = 8, .vsub = 16, },
-	{ .format = DRM_FORMAT_XBGR8888, .depth = 24, .num_planes = 2, .cpp = { 4, 1, }, .hsub = 8, .vsub = 16, },
-	{ .format = DRM_FORMAT_ARGB8888, .depth = 32, .num_planes = 2, .cpp = { 4, 1, }, .hsub = 8, .vsub = 16, },
-	{ .format = DRM_FORMAT_ABGR8888, .depth = 32, .num_planes = 2, .cpp = { 4, 1, }, .hsub = 8, .vsub = 16, },
+	{ .format = DRM_FORMAT_XRGB8888, .depth = 24, .num_planes = 2,
+	  .cpp = { 4, 1, }, .hsub = 8, .vsub = 16, },
+	{ .format = DRM_FORMAT_XBGR8888, .depth = 24, .num_planes = 2,
+	  .cpp = { 4, 1, }, .hsub = 8, .vsub = 16, },
+	{ .format = DRM_FORMAT_ARGB8888, .depth = 32, .num_planes = 2,
+	  .cpp = { 4, 1, }, .hsub = 8, .vsub = 16, .has_alpha = true, },
+	{ .format = DRM_FORMAT_ABGR8888, .depth = 32, .num_planes = 2,
+	  .cpp = { 4, 1, }, .hsub = 8, .vsub = 16, .has_alpha = true, },
 };
 
 static const struct drm_format_info *