drm/bochs: atomic: add mode_set_nofb callback.

Conversion to atomic modesetting, step two.
Add mode_set_nofb crtc helper callback.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20190111053752.4004-5-kraxel@redhat.com

drivers/gpu/drm/bochs/bochs_kms.c

@@ -86,6 +86,14 @@ static int bochs_crtc_mode_set(struct drm_crtc *crtc,
 	return 0;
 }
 
+static void bochs_crtc_mode_set_nofb(struct drm_crtc *crtc)
+{
+	struct bochs_device *bochs =
+		container_of(crtc, struct bochs_device, crtc);
+
+	bochs_hw_setmode(bochs, &crtc->mode);
+}
+
 static void bochs_crtc_prepare(struct drm_crtc *crtc)
 {
 }
@@ -149,6 +157,7 @@ static const struct drm_crtc_helper_funcs bochs_helper_funcs = {
 	.dpms = bochs_crtc_dpms,
 	.mode_set = bochs_crtc_mode_set,
 	.mode_set_base = bochs_crtc_mode_set_base,
+	.mode_set_nofb = bochs_crtc_mode_set_nofb,
 	.prepare = bochs_crtc_prepare,
 	.commit = bochs_crtc_commit,
 	.atomic_enable = bochs_crtc_atomic_enable,