rockchip: rk3399: spl: Mark printascii into debug

Now, we have spl_board_init with preloader_console_init that
indeed show SPL banner.

So mark the 'U-Boot SPL board init' print into debug.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/mach-rockchip/rk3399-board-spl.c b/arch/arm/mach-rockchip/rk3399-board-spl.c
index 65c98b6..890d800 100644
--- a/arch/arm/mach-rockchip/rk3399-board-spl.c
+++ b/arch/arm/mach-rockchip/rk3399-board-spl.c
@@ -164,7 +164,7 @@
 	 * printhex8(0x1234);
 	 * printascii("string");
 	 */
-	printascii("U-Boot SPL board init\n");
+	debug("U-Boot SPL board init\n");
 #endif
 
 	ret = spl_early_init();