Change 'repeatable' attribute of some commands to sensible values.

Most prominently this changes 'erase' to be non-repeatable.

Signed-off-by: Detlev Zundel <dzu@denx.de>
diff --git a/common/cmd_misc.c b/common/cmd_misc.c
index 67ee9e8..a99222d 100644
--- a/common/cmd_misc.c
+++ b/common/cmd_misc.c
@@ -63,7 +63,7 @@
 #endif  /* CONFIG_COMMANDS & CFG_CMD_IRQ */
 
 U_BOOT_CMD(
-	sleep ,    2,    2,     do_sleep,
+	sleep ,    2,    1,     do_sleep,
 	"sleep   - delay execution for some time\n",
 	"N\n"
 	"    - delay execution for N seconds (N is _decimal_ !!!)\n"