drm/i915: Only set CURSOR_PIPE_CSC_ENABLE when cursor is enabled

It seems cleaner if we keep CURCNTR at 0 when the cursor is disabled,
so don't set the CURSOR_PIPE_CSC_ENABLE bit unless the cursor is
enabled.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -8301,9 +8301,10 @@ static void i9xx_update_cursor(struct drm_crtc *crtc, u32 base)
 				return;
 		}
 		cntl |= pipe << 28; /* Connect to correct pipe */
+
+		if (IS_HASWELL(dev) || IS_BROADWELL(dev))
+			cntl |= CURSOR_PIPE_CSC_ENABLE;
 	}
-	if (IS_HASWELL(dev) || IS_BROADWELL(dev))
-		cntl |= CURSOR_PIPE_CSC_ENABLE;
 
 	if (intel_crtc->cursor_cntl != cntl) {
 		I915_WRITE(CURCNTR(pipe), cntl);