drm/i915: Fix i845/i865 cursor width

The change from the uapi coordinates to the internal coordinates
broke the cursor on i845/i865 due to src and dst getting swapped.
Fix it.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: 3a612765 ("drm/i915: Remove cursor use of properties for coordinates")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028113036.27553-1-ville.syrjala@linux.intel.comReviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/i915/display/intel_display.c

@@ -10947,7 +10947,7 @@ static void i845_update_cursor(struct intel_plane *plane,
 	unsigned long irqflags;
 
 	if (plane_state && plane_state->base.visible) {
-		unsigned int width = drm_rect_width(&plane_state->base.src);
+		unsigned int width = drm_rect_width(&plane_state->base.dst);
 		unsigned int height = drm_rect_height(&plane_state->base.dst);
 
 		cntl = plane_state->ctl |