command: Don't allow commands in SPL

At present we compile commands into U-Boot SPL even though they cannot
be used. This wastes space. Adjust the condition to avoid this.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/command.h b/include/command.h
index 0db4898..1b018cb 100644
--- a/include/command.h
+++ b/include/command.h
@@ -376,7 +376,7 @@
 	U_BOOT_SUBCMDS_DO_CMD(_cmdname)					\
 	U_BOOT_SUBCMDS_COMPLETE(_cmdname)
 
-#ifdef CONFIG_CMDLINE
+#if CONFIG_IS_ENABLED(CMDLINE)
 #define U_BOOT_CMDREP_MKENT_COMPLETE(_name, _maxargs, _cmd_rep,		\
 				     _usage, _help, _comp)		\
 		{ #_name, _maxargs, _cmd_rep, cmd_discard_repeatable,	\