drm/nvd0/disp: remove unnecessary sync from flip_next

This shouldn't be necessary, I believe this is just a bit of missed debug
code that got left over somehow.

Causes flips to be always synced to vblank, regardless of swap interval,
which we don't want..

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nvd0_display.c b/drivers/gpu/drm/nouveau/nvd0_display.c
index ccc20dc..7307d3f 100644
--- a/drivers/gpu/drm/nouveau/nvd0_display.c
+++ b/drivers/gpu/drm/nouveau/nvd0_display.c
@@ -284,8 +284,6 @@
 	u32 *push;
 	int ret;
 
-	evo_sync(crtc->dev, EVO_MASTER);
-
 	swap_interval <<= 4;
 	if (swap_interval == 0)
 		swap_interval |= 0x100;