ppc4xx: Do not stop booting on any keypress on dlvision-10g

Use CONFIG_AUTOBOOT_KEYED on dlvision-10g so that booting can only be
stopped with well defined keypresses.
Signed-off-by: NDirk Eibach <eibach@gdsys.de>
Signed-off-by: NStefan Roese <sr@denx.de>

include/configs/dlvision-10g.h

@@ -42,6 +42,10 @@
 
 #define CONFIG_SYS_CLK_FREQ	33333333 /* external frequency to pll   */
 
+#undef CONFIG_ZERO_BOOTDELAY_CHECK     /* ignore keypress on bootdelay==0 */
+#define CONFIG_AUTOBOOT_KEYED          /* use key strings to stop autoboot */
+#define CONFIG_AUTOBOOT_STOP_STR " "
+
 /*
  * Configure PLL
  */