drm/i915/fbc: Remove second redundant intel_fbc_pre_update() call

I fumbled the conflict resolution a bit when applying the
fbc vblank wait w/a. Because of that we now call intel_fbc_pre_update()
twice. Remove the second redundant call.
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191213133453.22152-2-ville.syrjala@linux.intel.comReviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

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

@@ -6043,9 +6043,6 @@ static void intel_pre_plane_update(struct intel_atomic_state *state,
 	    intel_fbc_pre_update(crtc, new_crtc_state, new_primary_state))
 		intel_wait_for_vblank(dev_priv, pipe);
 
-	if (new_primary_state)
-		intel_fbc_pre_update(crtc, new_crtc_state, new_primary_state);
-
 	/* Display WA 827 */
 	if (!needs_nv12_wa(old_crtc_state) &&
 	    needs_nv12_wa(new_crtc_state))