drm/i915: Remove user controllable DRM_ERROR for intel_get_pipe_from_crtc_id()

Don't emit a driver DRM_ERROR for a user passing in an invalid CRTC id,
simply report it is missing back to the user.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466773227-7994-12-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_display.c

@@ -14633,11 +14633,8 @@ int intel_get_pipe_from_crtc_id(struct drm_device *dev, void *data,
 	struct intel_crtc *crtc;
 
 	drmmode_crtc = drm_crtc_find(dev, pipe_from_crtc_id->crtc_id);
-
-	if (!drmmode_crtc) {
-		DRM_ERROR("no such CRTC id\n");
+	if (!drmmode_crtc)
 		return -ENOENT;
-	}
 
 	crtc = to_intel_crtc(drmmode_crtc);
 	pipe_from_crtc_id->pipe = crtc->pipe;