drm/sun4i: Fix uninitialized variables in vi layer

min_scale and max_scale in sun8i_vi_layer_atomic_check() can be used
without initialization.

Fix that.

Fixes: b862a648de3b ("drm/sun4i: Add support for HW scaling to DE2")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171206152603.25937-1-jernej.skrabec@siol.net

drivers/gpu/drm/sun4i/sun8i_vi_layer.c

@@ -253,6 +253,9 @@ static int sun8i_vi_layer_atomic_check(struct drm_plane *plane,
 	clip.x2 = crtc_state->adjusted_mode.hdisplay;
 	clip.y2 = crtc_state->adjusted_mode.vdisplay;
 
+	min_scale = DRM_PLANE_HELPER_NO_SCALING;
+	max_scale = DRM_PLANE_HELPER_NO_SCALING;
+
 	if (layer->mixer->cfg->scaler_mask & BIT(layer->channel)) {
 		min_scale = SUN8I_VI_SCALER_SCALE_MIN;
 		max_scale = SUN8I_VI_SCALER_SCALE_MAX;