sna: Force the shadow buffer even after we fail to set the crtc for TearFree

As the first choice of orientation and tiling may be invalid, e.g.
left/right rotation on Skylake, we need to force the second pass here to
try and an alternate non-native rotation.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

src/sna/sna_display.c

@@ -2841,7 +2841,7 @@ retry: /* Attach per-crtc pixmap or direct */
 
 		kgem_bo_destroy(&sna->kgem, bo);
 
-		if (!sna_crtc->shadow) {
+		if (!sna_crtc->fallback_shadow) {
 			sna_crtc->fallback_shadow = true;
 			goto retry;
 		}