rockchip: rk3399: spl: add missing \n to output

Without the patch SPL (in case of an error) creates an output like:

	U-Boot SPL board initMissing DTB

The patch adds the missing line feed. So now we get:

	U-Boot SPL board init
	Missing DTB

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

arch/arm/mach-rockchip/rk3399-board-spl.c

@@ -172,7 +172,7 @@ void board_init_f(ulong dummy)
 	 * printascii("string");
 	 */
 	debug_uart_init();
-	printascii("U-Boot SPL board init");
+	printascii("U-Boot SPL board init\n");
 #endif
 
 	ret = spl_early_init();