x86: Wrap print_ch() with config option

print_ch() should not be used if DEBUG_UART is off.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/x86_64/cpu.c

@@ -31,7 +31,9 @@ void arch_setup_gd(gd_t *new_gd)
 	 *
 	 * U-Boot SPL 2017.01
 	 */
+#ifdef CONFIG_DEBUG_UART
 	printch(' ');
+#endif
 }
 
 int cpu_has_64bit(void)