drm/rockchip: dw-mipi-dsi: use positive check for N{H, V}SYNC

This matches other drivers.

Signed-off-by: John Keeping <john@metanate.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170224125506.21533-20-john@metanate.com

drivers/gpu/drm/rockchip/dw-mipi-dsi.c

@@ -791,9 +791,9 @@ static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
 		break;
 	}
 
-	if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
+	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
 		val |= VSYNC_ACTIVE_LOW;
-	if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
+	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
 		val |= HSYNC_ACTIVE_LOW;
 
 	dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));